Defending champion Coco Gauff stumbles in Cincinnati as Putintseva pulls off upset

Gauff - who won last year's US Open to secure a first Grand Slam title - had no response as Putintseva took the last four games to battle to a 6-4 2-6 6-4 victory.

The American made more than 50 unforced errors in an erratic performance that included nine double faults.

"The whole match was a roller coaster," Putintseva said post-match.

"At this point, I was thinking I broke her a couple of times and it was not something special to break someone again. She hit two double faults, and I hit two good returns. She mishit it, the game changed immediately.

"On these kind of fast courts, you have to stay really focused, because the game can change quickly."

Aryna Sabalenka, set to move above American Gauff into the world number two spot when the rankings next update, comfortably saw off Italy's Elisabetta Cocciaretto 6-3 6-4 to move into the third round.

Former US Open finalist Leylah Fernandez knocked out number four seed Elena Rybakina, coming through 3-6 7-6 (3) 6-4 after being double match point down in the second set.

"I think it was an ugly match from the both of us, it clearly wasn't the best tennis," Fernandez said. "Clearly our service games weren't going well, too many unforced errors. I was just lucky that today I got the good end of the stick.

"I'm proud of the way I fought. It wasn't the prettiest match, but I accepted it and I just tried to enjoy that moment even though a lot of mistakes were coming."

Seventeen-year-old Mirra Andreeva beat veteran Czech Karolina Pliskova 6-2 6-3 to continue her progress.

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