KP6 not only Latvian taking city by storm

Third-seeded Garbine Muguruza got stunned by unheralded Anastasija Sevastova on Wednesday night at Arthur Ashe Stadium. Sevastova seemed stunned to have pulled off not only the biggest upset of the U.S. Open, but the biggest win of her career — either chapter of it.

After walking away from the sport for the better part of 18 months, Sevastova announced her return at the highest level. She handed the French Open champion an authoritative 7-5, 6-4 defeat, the f irst time Seva s tova has ever reached t he third round of a Grand Slam or downed a top-five foe.

“Really ?” said Se vast ova, catching a four-letter word on the tip of her tongue. “I don’t know. I was shaking a little bit at the end. It’s amazing. In Ashe, in night match? What’s going to be bigger?”

The 26-year-old Latvian took a commanding 5-1 lead, saw her Spanish foe climb all the way back to 5-4 and stave off two match points, eventually getting back on serve. But Sevastova, who shares a homeland with Knicks’ big man Kristaps Porzingis, steeled her nerves and solved enough questions to break her back and win.

“I have to solve my head, myself, all the thoughts: What could be, what could not? I’m so happy,’’ said Sevastova, who had quit in May 2013 after repeated injuries. “I was playing a little bit. I was doing some sparring. It was better, physically. I was still playing OK; that’s why I decided to try again to come back. But you never know. A lot of people are trying to come back, and sometimes it doesn’t work out.”

But its worked for her, Wednesday validating that comeback last year.

“For sure. It’s not like it’s my last match. It ’s still going on. It’s not like it’s over, the tournament. It’s only second round. … Yeah, it’s a good feeling. We can enjoy it today, but tomorrow is a new day.”

Sevastova had been ranked as high as 36th in the world five years ago, but back woes and ensuing depression forced her to retire. Now she’s glad both are behind her.

“I think it was a very tough match. I think I didn’t play well; I think she also played well. Everything she was doing was kind of working,’’ said Muguruza. “Maybe at the last part of the match we could feel we can have a chance to come back, but, in fact, was like 50/50. So at the end she played well, and that’s it.”