Images from the US Open men's singles first round matches, at Flushing Meadows, New York, on Monday.
Former champion Dominic Thiem's final appearance at the US Open ended tamely on Monday after he was beaten 6-4, 6-2, 6-2 in the first round by Ben Shelton of the United States.
The Austrian has struggled to reproduce the form that carried him to the 2020 Flushing Meadows title and announced he would retire from the sport this season after being troubled by a wrist injury in recent years.
Shelton leaned on his powerful forehand and sent over eight aces to open the action on Arthur Ashe Stadium, as the 21-year-old hopes to recapture the magic of his charmed run to the semi-finals 12 months ago.
Despite struggling with his serve, Thiem showed he had some fight left in him as he fended off two break points in the 10th game but a relentless Shelton forced him into an error to break him on the third attempt to take the opening set.
The American extinguished Thiem's lone break-point opportunity in the opening game of the second set and the Austrian handed Shelton a break in the second game with a double fault and an unforced error.
Shelton showed he could be a threat over the next two weeks as he broke Thiem again to close out the second set. He ran away with the match in the third set, pummeling 34 winners in a confident performance.
"Not much better atmosphere than being here at Ashe," said Shelton, who will next play Spain's Roberto Bautista Agut. "I'm glad that I had the opportunity to open it up here."
Thiem, who hoisted the trophy in front of empty stands in the midst of the COVID-19 pandemic, stayed back on court for ages on Monday to sign memorabilia for fans.
"I am super happy I got the chance to play my last US Open match on this court," Thiem said.
"I can now spend some time with you guys to say thank you to all of you and to make the time up that we missed four years ago."
Zverev flexes big serve in takedown of Marterer
Fourth seed Alexander Zverev out-duelled fellow German Maximilian Marterer 6-2, 6-7(5), 6-3, 6-2.
Zverev flexed his dominant serve, blasting 21 aces and winning 79 percent of his first serve points on the Grandstand.
Unseeded Marterer, the "lucky loser" that entered the draw after Emil Ruusuvuori withdrew last week, captured a close second set but was ultimately overpowered by the world No. 4.
Zverev looked sharp in the first set, breaking his opponent's serve in the opening game before Marterer battled back to claim a back-and-forth second set in a tiebreak.
The big-serving Zverev looked frustrated at times, tossing his racket at the start of the third set after committing one of 44 unforced errors.
The win sets up a second round clash with the winner of the match between Frenchman Alexandre Muller and Australia's Adam Walton later on Monday.
