A scary moment occurred at the Mubadala Citi DC Open on Monday when Yibing Wu, a 23-year-old tennis player from China, collapsed on the court. 

Wu was beating Yosuke Watanuki, 4-1, in the first set when the scary scene unfolded and forced him to retire from the match.

It was the second time in a matter of weeks that Wu had collapsed during a tennis tournament. 

Video footage showed Wu walking shakily toward a chair during a break in the action and then falling over near a ballboy.

Tournament staff rushed over to provide aid.

Wu was helped to his feet by two men briefly, footage showed, before still being too weak to stand and sitting back down on the court.

Since Wu was forced to retire from the match, Watanuk advanced from the Round of 64 in the Citi Open, which started Saturday and continues through Aug. 7.

The heat has been treacherous in Washington D.C., where the tournament is occurring, with the temperature sitting around 91 degrees at the time of Wu’s collapse.

Concerned tennis fans were hoping what occurred was solely related to the heat, but Wu also collapsed at Wimbledon last month. 

The Chinese tennis star was suffering from breathing problems during his match with Frances Tiafoe and appeared to collapse.

Wu was looked at by medics and found to have had a heart rate of 187, but after being cleared to continue, he did complete the match. 

Wu later claimed that he had been suffering from indigestion. 

“There was something wrong with the food I ate last night – I even felt like I was losing my consciousness out there,” Wu said at the time, according to the Daily Express. “I was better after my medical timeout, but it still affected my breathing. I feel good to play like I did, given my situation. I will go for a further check-up later.”

Wu is ranked No. 90 by the ATP Tour and has been as high as No. 54 during his career.

He made his Grand Slam debut in 2022 and became the first Chinese player to qualify for the U.S. Open, advancing to the third round.