Stuttgart, 1 Octover 2023 (dpa/MIA) — Olympic champion Alexander Zverev reached the quarter-finals of the China Open with a win against Alejandro Davidovich Fokina on Saturday in Beijing.

Like in Friday's match against Diego Schwartzman, Zverev again had health issues and seemed to have trouble breathing, but fought for a 6-7 (4-7), 6-2, 6-1 win.

He will now face Chile's Nicolas Jerry for a spot in the semi-finals.

"To be honest, I'm just tired right now, I want to go to bed. I also feel a bit sick," Zverev said after the match, which started at around midnight (1600 GMT) and ended at 2:45 am.

"Of course I'm happy with the win. It's difficult to play until three in the morning," he said.

Zverev hopes to further enhance his chances of playing at the season-ending ATP Finals for the eight best players of the year.

The Olympic champion is ranked seventh in this list and coming off his second title of the year in Chengdu.