WORLD No 1 Karolina Pliskova admitted she is struggling to cope with the pressure after surviving a major scare in the second round of the US Open.

The Czech top seed lost the first set to American Nicole Gibbs but recovered to win 2-6, 6-3, 6-4.

Pliskova has had a stellar 12 months, which began when she reached the final here, and she climbed to the top of the rankings after Wimbledon.

The 25-year-old said: “I think you cannot really see how I’m feeling inside. Even when I was playing some matches last year, two years before, I still have some nerves in myself.

“But I think now it’s even more. Every match, I have to win. There is enough pressure on me. They’re outsiders, so they’re always going to play well against me.”

Asked how the pressure affected her game, Pliskova said: “My legs, I felt a little bit slower in the first set. And my hands, as well. Then it’s tough to play like this. I have an aggressive game, so maybe if someone is defending it can work much better.”

The good news for Pliskova was that she managed to come through the match despite not playing her best, and she gave credit to Gibbs for her performance.

“Her level was quite high in the beginning of the match,” said Pliskova, who next meets 27th seed Zhang Shuai.

“I didn’t quite expect that she was going to play this way. She really was going for her shots. All credit to her.

“Overall I think it’s not even close to what I want to play today. I’m just happy that I went through. I think maybe this match can help me in the next matches just to play better, feel better. Maybe this is the match I needed in this tournament.”

There were more straightforward wins for fourth seed Elina Svitolina and French Open champion Jelena Ostapenko.

Both won by a 6-4, 6-4 scoreline, Svitolina against Evgeniya Rodina and Ostapenko over Sorana Cirstea.

A record was broken out on Court 10, where Shelby Rogers defeated 25th seed Daria Gavrilova 7-6 (8/6), 4-6 ,7-6 (7/5) in the longest women’s singles match in US Open history.

The pair were out on court for three hours and 33 minutes, 10 minutes longer than the previous record set by Johanna Konta’s second-round win over Garbine Muguruza two years ago.

Svetlana Kuznetsova became the fourth world No 1 contender to exit the women’s draw when she was beaten by Japan’s Kurumi Nara.

The eighth seed struggled with a wrist problem and had to save match points in her first-round win over Marketa Vondrousova on Wednesday so it was not surprising to see her in trouble again.

Kuznetsova battled back after losing the opening set but could not sustain her momentum as Nara prevailed 6-3 3-6, 6-3 for her first victory over a top-10 player.

Of those left in the tournament, only Pliskova, Garbine Muguruza, Svitolina and Venus Williams can now finish as No 1, while Simona Halep also remains in contention despite losing in the first round.

It was a good night for the home contenders, with 15th seed Madison Keys and Coco Vandeweghe, seeded 20, both progressing in straight sets.

Agnieszka Radwanska also eased into the third round.