Osaka squeezes into US Open third round

When pursuit of perfection wasn't panning out, Naomi Osaka managed to re-prioritise on Thursday and come away with a more important prize.

The two-time US Open champion defeated Katerina Siniakova 6-2, 5-7, 6-1 to reach the third round at Flushing Meadows, fighting through a frustrating second-set "dip" to seal the win.

Osaka looked in total control after racing through the first set and to a 4-2 lead in the second without facing a break point.

But as Osaka's unforced errors began to pile up — 20 in the second set compared to four in the first — doubles world number one Siniakova pounced, and Osaka's frustration with herself only made things worse.

"I think on my end it was more, like, mentally I wanted to play perfectly," said Osaka, who was broken as she served for the match at 5-3 in the second set as Siniakova rallied to force a third.

Osaka began berating herself after bad shots and smacked the edge of her racquet on the court after one poor point.

But she regrouped in the decider, riding a quick break to a 3-0 lead and fending off a pair of break points in the fifth game to make it 4-1 before breaking Siniakova one more time.

"In the third set, I just tried to do what I could do, and thankfully I was able to win," Osaka said.

"I had moments where I dipped, definitely. I feel like obviously on my serve I want to hold my serve at all times, and there were specific moments where I didn't.

"I was just really hard on myself, and it made me, I guess, over-analyze the situation.

"She's an amazing player, but I felt like I definitely had a lot of opportunities that I was a little bit too frantic. I was thinking too much about closing," added Osaka, who next faces Belgium's Elise Mertens — a 6-2, 7-6 (7/3) winner over Maria Timofeeva of Uzbekistan.