Czech fourth seed Karolina Pliskova was on the verge of becoming an early casualty at the U.S. Open but overcame Amanda Anisimova 7-5, 6-7(5), 7-6(7) in a thrilling second-round encounter on Thursday.

Pliskova bettered Julia Goerges's previous mark (21) for most aces in a women's match at Flushing Meadows set in 2019 and said her serve was key in getting her past the American. The tournament began recording the stat in 1998.

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"Of course, the serve was huge part of this win," she told reporters. "I thought we kind of pushed each other with the serve.

"I had a couple of break points ... but we didn't have many chances on the return. For women's tennis, normally there is break, break, break. That's quite impressive I think," she added.

Pliskova looked in control in the opening set after a single break separated the players. But American Anisimova, ranked 75th in the world, forced a decider when she won the second set tiebreak as the Czech made two double faults.

With the home crowd firmly backing Anisimova and cheering every point she won, the New Jersey-born 20-year-old fed off the energy at Arthur Ashe Stadium to save four break points and force another tiebreak.

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Pliskova found herself 2-5 down in the tiebreak, but she stormed back, saving a match point as Anisimova made three errors to hand the world number four a place in the third round.

"Super tough match, from the first moment she was playing very good," Pliskova said.

"It's difficult to play against you guys," she added, pointing at the crowd. "Hopefully, I don't have an American in the next round, two in a row is a lot... I'm shaking a bit."

Pliskova beat American Caty McNally in the first round. She will next face Australia's Ajla Tomljanovic, who defeated Croatian 30th seed Petra Martic 7-6(6), 6-4.