THE VIENNA: Dominic Thiem, the 2020 U.S. Open champion, said Wednesday that he tested positive for COVID-19 after his first match in more than nine months.
Thiem lost 6-3, 6-4 to Pedro Cachin at the Andalucía Open on the lower-level Challenger Tour on Tuesday.
The 28-year-old Austrian had been sidelined by wrist and hand injuries and last competed in June.
Thiem posted on social media that he "started feeling unwell and didn't have a good night" after dinner Tuesday and developed what he called mild symptoms.
He said he tested positive Wednesday.
Thiem was the runner-up at the French Open in 2018 and 2019, losing to Rafael Nadal each time, and at the Australian Open in 2020, losing to Novak Djokovic.
Later that year, Thiem collected his first Grand Slam title at Flushing Meadows, coming back from two sets down to beat Alexander Zverev in a fifth-set tiebreaker in the final.
Once ranked as high as No.3, Thiem is currently No.50.
Another past major champion, Stan Wawrinka, also made his return from injury at the Andalucía Open, losing his first match 6-2, 6-4 to Elias Ymer.
Wawrinka, who owns three Grand Slam singles titles and an Olympic gold medal won in doubles with Roger Federer, hadn't played in a year because of operations on his foot.