The 2020 US Open champion was making a return to tennis after long layoff

Dominic Thiem suffered a 6-3, 3-6, 6-4 loss to John Millman in the opening round of the Serbia Open yesterday in his first tour-level match in 10 months.
The 2020 US Open champion and former world number three had been sidelined with a wrist injury suffered in a grass court tournament in Marbella in June last year.
The 28-year-old Austrian returned to action in the same Spanish city last month in a second-tier Challenger clay court event where he lost in the first round.
He tested positive for Covid-19 the day after that defeat.
Thiem, a two-time French Open runner-up and 2020 Australian Open finalist, has slumped to 54 in the world during his prolonged absence.
The former world No 3 was competing in his first tour-level match since June following injury and he showed glimpses of what he is capable of during the two-hour, 35-minute clash against the Australian.
Thiem struck his backhand aggressively, but was unable to produce his best level, with Millman breaking in the 10th game of the third set to advance.
The 28-year-old, who played at an ATP Challenger Tour event at the end of March, is a 17-time tour-level titlist, with 10 of his victories coming on clay.
“It is great to be back here,” Millman said in his on-court interview.
“I was looking forward to coming back and play. All credit to Domi. I can’t claim it was one of my biggest wins because he is just coming back from injury and I know how hard that is, coming back from three surgeries myself. I know it has been tough for Domi but the game is better having him back. Especially on this surface. I have got to take this win because when he gets better and fitter, it is going to be tough.”
With his victory, Millman claimed his first win in four career meetings with Thiem. The World No. 80 will next meet Serbian Miomir Kecmanovic.
Also yesterday, Czech Jiri Lehecka overcame Henri Laaksonen 6-2, 7-5 to continue his strong start to the season. The 20-year-old, who reached the semi-finals in Rotterdam in February, is fifth in the ATP Race To Milan as he bids to make his debut at the 21-and-under event in November. Lehecka will next face second seed Andrey Rublev.
Serbian Laslo Djere recorded a win on home soil, defeating countryman wild card Hamad Medjedovic 6-4, 7-5, while Roman Safiullin downed Mikael Ymer 7-5, 6-0.
Eighth seed Filip Krajinovic, the only seeded singles player in action yesterday, advanced with a 6-3, 7-6(4) win over David Goffin on centre court, with fellow Serb Dusan Lajovic following to close out play against qualifier Taro Daniel. Lajovic would become the fifth Serb in the last 16 with a victory, including top seed Novak Djokovic.