NEW YORK (AFP) — Jessica Pegula scripted an astonishing comeback “just in the nick of time” to defeat Karolina Muchova on Thursday in the US Open and reach her first Grand Slam final, where she will take on big-hitting Aryna Sabalenka for the title.

The American world No. 6 Pegula battled back from a set and a break down to record a gutsy 1-6, 6-4, 6-2 victory over her 52nd-ranked opponent from the Czech Republic.

Double Australian Open champion and world number two Sabalenka reached her second successive US Open final by seeing off another American, Emma Navarro, 6-3, 7-6 (7/2).

“I thought I was lucky to still be in it,” Pegula admitted.

“She made me look like a beginner, she was destroying me and I was about to burst into tears, but it all came down to small moments. I don’t know how I turned that around.”

Pegula has now won 15 of 16 matches on the US summer hardcourt swing, which saw a title in Toronto and defeat in the Cincinnati final to Sabalenka.

“It’s a chance for revenge, but she’ll be tough to beat,” said Pegula, who has won just two of seven career meetings against the Belarusian.

Pegula, playing in her first Grand Slam semi-final after six painful quarter-final defeats, looked down and out at one stage on Thursday.

The 30-year-old lost the first set in just 28 minutes, was quickly 2-0 down in the second and had to save breakpoint to avoid slipping 3-0 down.

That was the cue for many spectators to leave the Arthur Ashe Stadium, not wanting to witness a second American defeat in quick succession.

But Pegula dug deep to spark an incredible recovery during a rollercoaster conclusion to a thrilling semifinal as she raced away with eight of the last 10 games.

“I was super-flat, I felt loose but maybe a little too loose,” Pegula added.

“But I was able to adapt just in the nick of time and to reach a final is a childhood dream.”

“If you’d told me at the start of the year that I’d get to a Grand Slam final I would have laughed so hard at you.”

Muchova, a semifinalist also in 2023 before going on to miss 10 months due to a serious wrist injury, committed her 40th unforced error of the contest on match point, sealing her fate.

“I had a breakpoint for 3-0 in the second set but I missed a volley and everything changed,” Muchova said.

“She picked it up and played solid. She was everywhere and played great. All credit to her.”

Sabalenka, the runner-up to America’s Coco Gauff last year, went through to the final by seeing off Navarro as well as a partisan home crowd.

Navarro, playing in her first semifinal at the majors, went down fighting when she clawed her way back from 3-5 in the second set to force the tiebreak.

Sabalenka cracked 34 winners to the 13 of the 23-year-old American as she moved one win away from a third Grand Slam title.

“Guys, now you’re cheering for me. Wow. It’s a bit too late,” Sabalenka, 26, told the Arthur Ashe Stadium crowd.