NEW YORK (AP) Milos Raonic's face was red, his body was the very picture of weariness. His left wrist was bothering him. So was his left thigh.
A Wimbledon finalist just last month, and seeded No. 5 at the U.S. Open, Raonic double-faulted 15 times and was stunned in the second round at Flushing Meadows 6-7 (4), 7-5, 7-5, 6-1 on Wednesday by Ryan Harrison, a qualifier from the United States ranked only 120th.
For Harrison, a 24-year-old born in Louisiana and now based in Texas once seen as possibly the ''next big thing'' in American men's tennis, this is his first trip to the third round at a Grand Slam tournament. He had been 0-6 in second-round matches.
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Until Monday, Harrison hadn't even won a single main-draw match at any major since the 2013 French Open.
Last week, Harrison and his younger sibling Christian, 22, became the first pair of brothers to both qualify for the U.S. Open.
''I'm excited to keep moving forward,'' Harrison said during an on-court interview at the tournament's new Grandstand stadium, telling the partisan crowd: ''Anything's possible when I have your support.''
The fans pulled for their guy loudly with all sorts of chants, including, ''Here we go, Ryan! Here we go!''
And while he was certainly helped by his opponent's myriad problems – Raonic received repeated visits from a trainer, who worked first on the Canadian's wrist, then massaged his leg – Harrison played cleanly after recovering from a double-fault that ceded the opening set.
He wound up with 33 unforced errors, making merely one in the final set of the 3+-hour match. Raonic's total was 62, including a whopping 21 in the third set alone.
After Harrison hit a cross-court forehand passing winner to break for a 5-1 lead in the fourth set, Raonic looked exhausted as can be, resting both arms on his knees behind the baseline and leaning on his racket for extra support.
Raonic was a semifinalist at Wimbledon in 2014 and the Australian Open this January. Then he beat Roger Federer in the semifinals at the All England Club in July to reach his first Grand Slam final, before losing to Andy Murray.
Now he's the highest-seeded player to exit the U.S. Open so far. And Harrison finally has the sort of breakthrough victory that was predicted long ago for him. He entered Wednesday with a 1-26 record for his career against top-10 opponents, including 0-8 at majors.
In the third round, Harrison will face 44th-ranked Marcos Baghdatis of Cyprus, the 2006 Australian Open runner-up. Baghdatis eliminated 32nd-seeded Benoit Paire of France 6-2, 6-4, 3-6, 6-4 on Wednesday.
Raonic was not the only player to struggle physically on a day the temperature was in the mid-80s. Johanna Konta, the tournament's 13th-seeded woman, collapsed and received medical treatment right out there on Court 13 late in the second set of her 6-2, 5-7, 6-2 victory over Tsvetana Pironkova. Konta said her heart was racing and she had trouble breathing.
In other action, two-time U.S. Open runner-up Caroline Wozniacki beat a top-10 opponent for the first time in nearly a year, turning things around after dropping the first four games and eliminating 2004 U.S. Open champion champ Svetlana Kuznetsova 6-4, 6-4.
A former No. 1, Wozniacki is currently ranked 74th after dealing with an ankle injury and a series of losses.
''I always believe in myself,'' said Wozniacki, unseeded in New York for the first time since her 2007 tournament debut, ''and I always think that in my head I belong at the top of the game.''
She lost in the finals at Flushing Meadows in 2009 and 2014.
The woman who surprised Serena Williams in the semifinals on the way to a runner-up finish in 2015, Roberta Vinci, moved into the third round for the sixth consecutive year, defeating Christina McHale of the U.S. 6-1, 6-3.
The defending men's champion, Novak Djokovic, did not need to play a point Wednesday to reach the third round: His opponent, 49th-ranked Jiri Vesely of the Czech Republic, withdrew a couple of hours before their match, citing inflammation in his left forearm.
Vesely, who beat Djokovic on clay in Monte Carlo in April, said the muscles were starting to pinch a nerve, causing numbness.
''Playing Novak,'' Vesely said, ''you have to be 100 percent ready.''
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