British number one Jack Draper fought back from a set down to beat Stefanos Tsitsipas and reach the Cincinnati Open third round.
Tsitsipas, ranked 11th in the world, broke for 5-4 in the deciding set, but Draper won 12 of the last 17 points to wrap up a 3-6 6-4 7-5 victory.
“In general my grit, my determination and attitude won me the game today, so I am very proud of that,” Draper, the world number 28, said in his on-court interview.
The 22-year-old will face Norwegian seventh seed Casper Ruud or Canada’s Felix Auger-Aliassime next.
Tsitsipas, a former runner-up at the Australian Open and French Open, was playing in his first tournament since stopping his coaching partnership with his father Apostolos.
In the opening round of the women’s event, defending champion Coco Gauff was beaten 6-4 6-2 6-4 by Kazakh world number 34 Yulia Putintseva.
“I feel like I have to work on consistency, overall,” Gauff, 20, said.
The US Open champion will lose her world number two spot to Aryna Sabalenka, who claimed a comfortable 6-3 6-4 win against Italy’s Elisabetta Cocciaretto.
Fourth seed Elena Rybakina failed to convert two match points before Canada’s Leylah Fernandez progressed with a 3-6 7-6 (7-3) 6-4 victory.
Men’s world number four Alexander Zverev defeated Karen Khachanov 6-3 6-2, while sixth seed Andrey Rublev saw off China’s Zhizhen Zhang 6-4 6-3.