Jessica Pegula has shrugged off a sluggish start and come back from a set and a break down at the US Open to defeat Karolina Muchova 1-6 6-4 6-2 for a berth in her first grand slam final.

The No.6-seeded Pegula, a 30-year-old from New York, has won 15 of her past 16 matches and will meet world No.2 Aryna Sabalenka for the title on Saturday.

It will be a rematch of last month's final at the hard-court Cincinnati Open, which Sabalenka won ? the only blemish on Pegula's post-Olympics record.

"Hopefully I can get some revenge out here," said Pegula, whose parents own the NFL's Buffalo Bills and NHL's Buffalo Sabres.

"Playing Aryna is going to be really tough."

Sabalenka, last year's runner-up to Coco Gauff at Flushing Meadows, returned to the championship match by holding off a late push to beat 13th-seeded American Emma Navarro 6-3 7-6 (7-2) earlier on Thursday.

Things did not look promising for Pegula early. Muchova, the 2023 French Open runner-up but unseeded after missing about 10 months because of wrist surgery, hit 10 of the match's first 12 winners. The opening set lasted 28 minutes, and the Czech won 30 of its 44 points.

Muchova grabbed eight of the first nine games and was one point from leading 3-0 in the second set. But she couldn't convert a break chance there, flubbing a forehand volley, and everything changed.

Quickly, the 52nd-ranked Muchova went from not being able to miss a shot to not being able to make one. And Pegula turned it on, demonstrating the confident brand of tennis she used to eliminate top seed Iga Swiatek, a five-time major champion, in straight sets. Pegula had been 0-6 in major quarter-finals before that breakthrough.

"I came out flat, but she was playing unbelievable. She made me look like a beginner," Pegula said.

"I was about to burst into tears, because it was embarrassing. She was destroying me.

"I was able to find a way, find some adrenaline, find my legs. And then at the end of the second set, into the third set, I started to play like how I wanted to play. It took a while ... I don't know how I turned that around."

Sabalenka moved into her second consecutive US Open decider by taking the last seven points in the tiebreaker against Navarro.

The 26-year-old Belarusian who won each of the past two Australian Opens, never let the spectators play too much of a role until things got quite tight in the second set.

Knowing she would be facing a player from the US in this semi-final, Sabalenka joked after her previous match she would try to sway them to her side by buying booze, saying: "Drinks on me tonight?"

Navarro did not fold in the second set, despite trailing for much of it, and she broke when Sabalenka served for the victory at 5-4.

But in the breaker that followed, after Navarro led 2-0, Sabalenka took over, grabbing every point that remained.

"I was like, 'OK, Aryna, you have to stay focused. Stay in your thoughts. Focus on yourself,'" Sabalenka said.

"And, yeah, I was thinking a lot."