Sept 5, 2022; Flushing, NY, USA; Jessica Pegula of the USA hits to Petra Kvitova of the Czech Republic on day eight of the 2022 U.S. Open tennis tournament at USTA Billie Jean King National Tennis Center. Mandatory Credit: Robert Deutsch-USA TODAY Sports

NEW YORK, Sept 5 (Reuters) - A surprise shower failed to stop American Jessica Pegula from reaching her third Grand Slam quarter-final this year as she toppled twice Wimbledon champion Petra Kvitova 6-3 6-2 at the U.S. Open on Monday.

One of the most reliable returners in the sport, Czech Kvitova had won both of their previous meetings but was left to rue her missed chances -- as she converted only two of the six break points she earned.

Rain forced a 44-minute stoppage early on in the match, with tournament staff scrambling to close the retractable roof on Ashe and mop up the court.

But eighth seed Pegula was unfazed as she broke Kvitova to love in the seventh and ninth games to close out the first set.

Even when Kvitova took a 2-0 lead in the second, Pegula kept her nerve to storm back and win the next six games to wrap up the win.

"I was just (thinking), 'Okay, don't get frustrated, she hit a couple good shots. Stick to your patterns'," Pegula said after she joined fellow American Coco Gauff in the last eight. "For me, my placement on my serve was very important. She can really hit it so early so out in front and hit her spots so well.

"That makes it really hard to defend. Even if you get back the first ball of a return you're probably going to lose the point."

She next faces world number one Iga Swiatek, who needed three sets to tame 108th-ranked German Jule Niemeier.

"I just have to play smart...," said Pegula. "I thought I did a great job of that today so I'm going to try and replicate that."

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