The crowd serenaded the No. 3 seed from Greece with a rendition of “Happy Birthday” as he was presented with a white sheet cake decked out with fresh fruit.
“One of the best feelings you can experience on a tennis court,” said Tsitsipas, who is ranked No. 3 and lost this year’s French Open final to Novak Djokovic in five sets.
Tsitsipas dominated his Russian opponent, saving both his break points and winning 74% of his service points.
He next faces Casper Ruud of Norway in the quarterfinals Friday. The pair met at the Madrid Open in May, with Ruud winning in straight sets in the round of 16.
“I’m looking for a change, looking for a switch-up this time,” Tsitsipas said.