Yedlin's challenge sees Quintero's shot deflect through to Howard - and that will be it...
89'
Yedlin, usually such an attacking threat, has had no need to go forward today. Arriola has been superb on the wing. His latest cross is just about cleared.
88'
Wood is furious after he's brought down. Meanwhile, Dempsey is onside and just a yard away from meeting Bedoya's cute pass into the box and surely scoring.
87'
Penedo, under pressure from two angles, passes the ball straight out of play. This is pretty desperate stuff from the visitors.
86'
Their game may be over, but Panama's foul count continues to rise. Cooper takes down Dempsey on the left.
85'
Panama have the ball, but this move does not look to be going anywhere. The States are very comfortable and Yedlin then catches Gabriel Torres offside.
82'
Much easier for Penedo this time. A neat corner routine passes through Bradley and McCarty, before Bedoya prods tamely at the goalkeeper.
81'
SAVE! Brilliant play all round! McCarty measures a pinpoint pass through for Arriola. He looks to be in for the fifth, but Penedo does well to deflect the shot just wide.
79'
A. Bedoya enters the game and replaces D. Nagbe.
SUB! Nagbe is off and Alejandro Bedoya is given his chance.
Panama's corner comes to little as a header sails over the crossbar.
78'
Quintero runs at Yedlin again after USA lose the ball in the midfield, but the Newcastle man deflects a tame shot behind for a corner.
Minute
Description
75'
Wood and Cooper clash off the ball. There's nothing in it, but the American forward really does not need to get involved there. He almost gets in again as USA break.
73'
Quintero has attempted to thrill for the visitors, but Yedlin has too often closed him out of the game. Another block follows. And Gonzalez then tumbles into the crowd under pressure from Gabriel Torres, to consternation from Howard.
72'
Dempsey immediately clashes with Roman Torres - a club team-mate - but the defender comes out on top in a duel on the corner of the area. Strong defending.
71'
C. Dempsey enters the game and replaces J. Altidore.
SUB! As Nagbe wins a free-kick in a promising position, Dempsey replaces two-goal Altidore.
Bradley takes the set-piece short and the States keep the ball.
69'
McCarty cheaply gives up possession, but Panama's cross from the left is claimed uncontested by Howard. USA are cruising.
68'
The chants go on. "Dempsey, Dempsey..." This game is well won and the action is almost secondary for the fans right now. Dempsey readies himself on the touch line.
67'
"We want Dempsey," chant the crowd. Seattle Sounders forward Dempsey is tied with Landon Donovan as the States' all-time record scorer.
66'
Arriola has been excellent today, too. He crosses just beyond Nagbe, with Wood pushing a strong pass into Altidore. The Toronto man pokes harmessly over the top.
64'
And discomfort straight away for Wood! Godoy catches the scorer in a rather sensitive area. After a minute or two, he's fit to continue.
63'
B. Wood has scored a goal for United States! Assist by P. Arriola.
McCarty brilliantly kept the move alive in the middle, finding Wood, who pushed the ball on to Arriola and then took the return pass after the midfielder ignored Yedlin's overlap. Don't forget Panama led USA in the Hex ahead of this one. Four!
GOAL! Now he has his goal! Wood really deserves that one. He controls in the area and calmly strokes into the bottom-left corner. 4-0.
62'
CHANCE! Oh so close for Wood, whose goal just will not arrive! Without the support of Pulisic this time, he runs at the Panama defence again, shifting the ball past Roman Torres to create an angle. The shot is wide, though.
60'
A. Arroyo enters the game and replaces B. Pérez.
SUB! Perez, formerly of FC Dallas, makes way. On comes Abdiel Arroyo.
59'
SAVE! And, on that same right flank, Arriola gets in behind. His shot is hard and low and straight at Penedo.
58'
Freed by the introduction of a holding midfielder, Yedlin instantly pushes up on the right. His cross just evades Altidore.
Panama then have an opportunity to attack at the other end, but Gabriel Torres' touch in to Quintero is frustratingly too strong.
57'
D. McCarty enters the game and replaces C. Pulišić.
SUB! Arena, surely wary of the rough treatment being handed out to Pulisic, replaces his star man with Chicago Fire's Dax McCarty.
Bradley's free-kick came to nothing, Roman Torres comfortably nodding clear.
56'
Finally a free-kick! Arriola is chopped down 30 yards from goal.
Wood takes on two players, three players, before finally being halted by Roman Torres - perhaps inadvertently. He had Pulisic in on his left.
55'
The States are just keeping the ball now, looking to move it quickly enough to avoid any kicks.
53'
SAVE! A foul is finally given - but it goes in favour of Panama. Gabriel Torres' free-kick finally reaches Roman Torres, whose volley is gathered by Howard under pressure.
52'
USA could reasonably complain about the lack of protection they are getting from the referee here. Wood is the latest to be fouled without so much as a free-kick awarded. This second half has not been quite so freeflowing.
51'
Another heavy challenge on Pulisic! Godoy smashed the Borussia Dortmund man as he plays a pass. Panama are unable to gain an advantage as Villafana halts the attack.
50'
The game continues as Pulisic jogs up and down the touchline after a conversation with Arena. He looks to be ready to come back on as Panama have an injury of their own - Cooper slowly picking himself up.
And Pulisic returns to the field.
49'
Pulisic has had some treatment and hobbled to the side of the pitch. His sharp turn was about to make a mockery of Murillo.
48'
A. Murillo gets yellow.
YELLOW! Pulisic has been kicked and kicked, not helped by his continued embarrassing of the Panama defence. Murillo has had enough and takes a booking - that brings a suspension - to bring the teenager down.
46'
F. Escobar enters the game and replaces F. Baloy.
SUB! Baloy has had a torrid time; he's replaced by Escobar, whose place he took in the team.
KICK-OFF: The States gets us started again.
Panama have just been so sloppy. Murillo gifts the ball to Nagbe, recovering to win possession back. USA could have broken again, though.
45' +1
HALF-TIME: United States 3 Panama 0.
45'
CHANCE! Yedlin, one booking from a suspension, concedes a foul, but he avoids a yellow card. Godoy flicks Gabriel Torres' free-kick over the top.
44'
Who doubted the States? Who doubted Altidore? Nobody is now...
43'
Penalty goal scored by J. Altidore for United States!
GOAL! Oh, Altidore! That is exquisite! He delicately lifts the penalty kick down the middle of the goal, with Penedo diving to his left. 3-0.
42'
A. Cooper gets yellow.
YELLOW! Cooper is booked for that foul.
PENALTY! Wood may have passed up chances, but his running has been sublime and wins a spot-kick now! He charges beyond Cooper, who drags him down.
41'
SAVE! Excellent goalkeeping from Penedo! Pulisic brilliantly frees Arriola, who in turn picks out Wood. The forward slips a pass through Roman Torres' legs for Altidore, but the scorer of the second goal attempts to round Penedo for a third and is halted.
40'
Altidore and Wood again create space for Pulisic to run into, but the youngster gets the pass wrong this time with Panama backtracking.
39'
More good defending from Yedlin, blocking Perez's shot on the left of the area. He then nods clear another cross and races over to prevent the corner.
37'
Bradley is a little exposed in the middle - particularly one card away from a suspension - but he is just about toeing the line right now.
36'
There's more commotion in the middle, allowing Panama to clear, but Yedlin halts the counter. Bradley is adjudged to be offside when the ball heads back up the other end.
35'
From the free-kick, Gonzalez wins a corner on the States' right...
34'
F. Baloy gets yellow.
YELLOW! Baloy, who could have been sent off earlier, has the cheek to appeal against a blatant booking for chopping down Wood.
32'
Arena still looks a little nervy on the touchline, despite the lead. The game is still flowing from end to end.
31'
Torres' namesake Roman is dangerous from the set-piece, with the hosts scrambling the ball behind for another corner. This time Bradley clears.
30'
Panama attempt to take a more patient approach, but the hosts' energy is just too much for them. Godoy has nowhere to go, playing the ball back to Penedo who nearly gifts possession away again.
SAVE! Villafana is too often leaving a man on the left of the home defence and he's grateful to Howard! The Colorado Rapids goalkeeper blocks well from Gabriel Torres.
28'
Murillo just about halts another break through Wood, giving away a throw-in on halfway. The States are just tearing through the Panama defence at will.
27'
BLOCK! Superb challenge from Yedlin! Quintero dances past both Besler and Gonzalez, but the Newcastle United defender is across to dive into a stunning block. Crucial.
26'
A. Cooper enters the game and replaces Y. Bárcenas.
SUB! Panama coach Gomez has seen enough. He withdraws Barcenas for Altidore's Toronto team-mate Armando Cooper.
25'
OFFSIDE! Pulisic is running wild! He intercepts a woeful clearance and slips in Altidore again. The finish is wide, but Altidore was offside.
24'
Bradley's set-piece is punched straight up in the air by Penedo, but Gonzalez takes a whack as he challenges for the second dropping ball. USA knock the ball out, but the defender is fit to continue.
23'
Villafana wins a corner on the left for the States, but his cross cannoned away off Murillo's face and the visiting defender is taking his time to get back to his feet.
22'
SAVE! It should be three, it really should! Wood is set through by Arriola's pinpoint pass, but he just takes too long to shoot and blasts straight at Penedo. Pulisic's follow-up is nodded away.
21'
Panama are desperately attempting to cut off the route to Pulisic - and manage it this time. Quintero crosses at the end of a speedy attack, but Besler and Omar Gonzalez see the ball clear.
20'
As things stand: USA are into third place, good enough to qualify automatically. There is still another game to play, however.
19'
J. Altidore has scored a goal for United States! Assist by C. Pulišić.
Pulisic predictably provides the assist, dashing away down the left to drill in a fine centre.
GOAL! It's two for the States and it's Altidore! Panama cannot cope with this front line and the Toronto man is in the middle to tuck home a low cross. 2-0.
18'
Almost a chance for the visitors! Yedlin holds up Barcenas on the right, but the cross still reaches Quintero in the area. He cannot quite tease a pass through to Perez.
17'
Perez wastes the opportunity, however, fouling his man before the corner even reaches the box. Free-kick to the hosts.
16'
Corner to Panama now. Murillo's cross deflected but Howard was certain he kept the ball in play. The linesman thinks otherwise...
15'
Perez wins a free-kick with a neat dribble at the other end, allowing Panama to put some pressure on. Nagbe clears, though.
13'
Baloy - an experienced campaigner - looks to have elbowed Besler. He's fortunate to escape censure.
CLOSE! Finally the corner comes in and reaches Altidore at the back post, but he thumps a volley just wide.
12'
Besler appears to be lying in the middle of the penalty area following some jostling ahead of the corner. He has a cut to his eye and will need some attention. It's not entirely clear what happened there.
11'
Darlington Nagbe gives the ball away cheaply in the midfield, but USA clear from the subsequent attack and counter. Pulisic is off and running again, winding through challenges to win a corner in the area. Brilliant.
10'
This game does not look like slowing...
9'
Penedo is almost caught out again immediately as he races from his goal line, but the former LA Galaxy goalkeeper just about clears.
8'
C. Pulišić has scored a goal for United States! Assist by J. Altidore.
Similarly to Panama's prior attack, the goal stemmed from a long ball and a won aerial duel. Wood nods on towards Altidore who played in Pulisic.
GOAL! What a start, what a goal! It's Pulisic, the boy wonder, of course! He tears past Roman Torres and then rounds Jaime Penedo to net from a tight angle. That is a massive goal. 1-0.
7'
CHANCE! Another big opportunity at the other end! Perez wins a flick-on to tee up Gabriel Torres, who controls well and finds space but shoots well wide.
6'
Arriola is lining up on the right, in front of Yedlin, and he has been busy hassling the visiting back line already. This has been a handy enough start for Arena's side.
5'
CHANCE! A huge opening for Wood! Pulisic wins a free-kick from Godoy and, although Bradley's delivery is cleared, Altidore sends in a second cross and his strike partner prods wide.
4'
USA are seeking out various routes to goal and the latest sees Bobby Wood cross deep to Arriola, whose ambitious volley flashes across the edge of the box.
3'
BLOCK! Almost a first chance and Christian Pulisic is, of course, central. He dances away from a challenge and plays in Altidore, whose shot is blocked by Murillo. Panama escape.
2'
The States, in their red shirts, are now enjoying some possession, with Yedlin again involved.
1'
KICK-OFF: Blas Perez gets us started for Panama.
Panama make a bright start, but Yedlin's speed allows him to recover and win a free-kick in defending an attack down his flank.
Hello and welcome to this huge clash between the United States and Panama in the CONCACAF section of qualifying for the 2018 World Cup!
All is not well for Bruce Arena's men as they gear up for this game in Orlando. They trail Panama by a point and currently occupy the play-off berth in the Hexagonal - the fifth qualifying round - but a failure to collect the three points here could see Honduras leapfrog USA with victory against Costa Rica tomorrow.
Even if the States were to hold on to that fourth spot, CONCACAF has been paired with AFC in the play-off round. A two-legged tie against either Australia or Syria would be far from a formality. Arena and his team need a win.
A column from former FC Dallas midfielder and soccer pundit Bobby Warshaw this week described this as USA's "biggest match ever". There is an awful lot riding on this fixture for the home side.
United States (4-1-3-2): Howard, Yedlin, Gonzalez, Besler, Villafana, Bradley, Nagbe, Arriola, Pulisic, Altidore, Wood.
Will "San Zusi" strike again for USA? Let's get the team news...
Panama (4-4-2): Penedo, Murillo, Roman Torres, Baloy, Ovalle, Barcenas, Gomez, Godoy, Quintero, Perez, Gabriel Torres.
The hosts have favoured a three-man defence of late - disastrously experimented with under previous coach Jurgen Klinsmann - but it appears there was no truth in rumours suggesting Arena would go that way again here.
Tim Howard, Jorge Villafana, Paul Arriola and Bobby Wood come into the side, having missed out in Honduras last time out. Jozy Altidore returns from suspension, while DeAndre Yedlin is also back after an injury as Zusi drops to the bench.
And there is history between these two outfits, too. Panama were denied a play-off place at the death in qualifying for the 2014 World Cup as the States' Graham Zusi scored a stoppage time equaliser, ahead of Aron Johannsson's winner, to hand rivals Mexico fourth spot in the Hex.
Three players in the Panama line-up - and a further three substitutes - play their club football in MLS; they should know Florida's Orlando City Stadium well. It boasts one of the most fervent atmospheres in the country and USA will hope to use that to their advantage in this one.
Something to keep an eye on, however: television cameras appear to have picked up Altidore suffering from a knock in the warm-up. The Toronto FC forward looks to be grimacing and stretching out his leg. We will, of course, bring you any further developments on the 27-year-old...
ESPN are reporting Altidore will line up, as expected, in the home team despite that late scare. That's good news for Arena, who cannot afford any such misfortune at this late stage.
For Panama, a win here would put them on the brink of World Cup qualification for the very first time - not that they will be counting their chickens after previous disappointments.
Hernan Dario Gomez's men - like the States - have tasted victory only twice in the Hex in this campaign. They drew the home fixture against USA after Gabriel Gomez cancelled out a Clint Dempsey opener, while their previous four away qualifiers have brought a total of just three goals.
We are around 10 minutes from kick-off...
And here come the teams. What a roar!
We're one anthem down. The Panamanians know how to belt out a tune - both on the pitch and in the stands. The away players look determined, focused. This is huge for them, too.
The Star-Spangled Banner follows, with a visual display of flags and fireworks met with further cheers. We are just about ready for this one.
It's worth noting there are numerous players one booking away from a crucial suspension here. For USA, that involves Yedlin, Matt Besler, captain Michael Bradley and Arriola. The visitors could lose Michael Murillo, Luis Ovalle, Anibal Godoy, Gomez, Edgar Barcenas and Alberto Quintero.
Here we go!
Chants of "USA, USA" are broken up for a minute's silence in memory of the victims of the terror attack in Las Vegas last week.
The visitors make just the two changes as captain Felipe Baloy - the 36-year-old - and Jaime Penedo are brought in for Fidel Escobar and Jose Calderon.
What a half! "We're a little sloppy," Arena is telling ESPN. His side are three goals to the good.
Pulisic opened the scoring from Altidore's pass and then returned the favour, before Wood won a penalty for his strike partner to notch a second. It could have been more than three, too.
It has been open, Panama have had their chances, but USA's quality on the break has destroyed the visiting defence. Pulisic, Wood and Altidore have been superb.
USA return to winning ways, allowed to take their foot off the pedal after the break. Pulisic and Altidore (twice) had earlier scored, with Wood getting on the scoresheet in the second period.
That's all from Orlando, where USA have responded to their critics with a huge win over Panama. Thanks for joining us and, until next time, goodbye!
That result sees the States climb above Panama into an automatic spot with one game remaining. That match is against Trinidad and Tobbago, who are out of contention with this result. Their task always looked improbable.
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