No.1 seed Karolina Pliskova has suffered a shock 6-1 7-6 (7-2) loss to Frenchwoman Caroline Garcia to crash out of the US Open.

Pliskova, a former world No.1, had no answer to the power of Garcia who fired 30 winners to the Czech’s 13 on Wednesday.

“This (seeding) has nothing to do with my loss today,” Pliskova told reporters. “I think there are just some girls who are playing good tennis … Garcia is one of them.

“I think she played amazing set and a half. Of course I got my chances later in the second set.”

Pliskova went 5-0 down in the opening set and although she fought back in the second, Garcia dominated the tie-break to advance.

“It was very close to being a third set and if so I was ready,” said Garcia. “When I got broken in the second set I didn’t do anything really bad, and I had to stay focused and aggressive.”

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In a day of upsets, seeds Elena Rybakina (11), Marketa Vondrousova (12) and Alison Riske (13) all bowed out.

Shelby Rogers defeated Rybakina 7-5 6-1 while Ann Li beat Riske 6-0 6-3.

French Open finalist Vondrousova was beaten by Belarusian Aliaksandra Sasnovich 6-1 6-2.

Vondrousova endured a disappointing outing with her 16 winners overshadowed by 21 unforced errors.

Naomi Osaka maintained her winning streak prior to the third round with a statement 6-1 6-2 victory over Italian big-hitter Camila Giorgi.

The Japanese-Haitian star stepped onto the court wearing a mask emblazoned with the name of Elijah McClain, a young black man who died after police in Colorado restrained him using a chokehold.

Osaka, who played with her left hamstring strapped, dropped a mere five points on serve.

Petra Kvitova overcame a bout of nerves and a rocky start to defeat Kateryna Kozlova 7-6 (7-3) 6-2 in her second-round clash.

Czech sixth-seed Kvitova was off her game early on, committing 20 unforced errors during the first set – twice as many as her Ukrainian opponent – as she struggled with her serve.

The two-time Wimbledon champion committed a fifth double fault to hand Kozlova a break point and a 3-2 lead in the first set but recovered to save set point at 5-4 and eventually took the opener on a tiebreak.

Former champion Angelique Kerber came through a fierce all-German tussle against Anna-Lena Friedsam 6-3 7-6 (8-6) to book her place in the third round.

Kerber, seeded 17th, moved into a 3-0 lead but 109th-ranked Friedsam settled down and made her more illustrious compatriot work hard for victory.

Friedsam, who suffered first-round exits on both her previous main draw appearances at Flushing Meadows, grew increasingly confident and worked tirelessly to force the left-hander into a tiebreak before losing on Louis Armstrong Stadium.

“It was really a tricky match and when you play against a German it’s never easily mentally,” said Kerber, playing in her 50th grand slam tournament.

France’s Kristina Mladenovic complained of living a “nightmare” due to the COVID-19 health protocols in New York after suffering a spectacular second-round meltdown to Russian Varvava Gracheva.

Mladenovic looked set for a breezy win while serving at 6-1 5-1 but things went downhill for her abruptly and she ended up losing 1-6 7-6 (7-2) 6-0.

“It’s absolutely abominable how they are treating us, but I don’t want that to be an excuse for my defeat,” she said.

“It’s not the USTA’s fault that I didn’t convert four match points, don’t get me wrong.

“At 5-2, I just collapsed. I have nothing more to say, I’m completely devastated.

Mladenovic was one of several athletes placed under an “enhanced protocol plan” for being in contact with compatriot Benoit Paire, who tested positive for the novel coronavirus and was withdrawn ahead of the Grand Slam.

Mladenovic said despite “thirty negative tests” she was still treated like a prisoner and a criminal.

“We’re living a nightmare here. I have only one desire and that is to regain my freedom,” the 44th-ranked Mladenovic told reporters.

“The conditions are atrocious and if I had known that playing cards for 40 minutes with a player who tested positive, but ultimately negative, would have resulted in these consequences, I would never have set foot in this tournament.”

-AAP