Reigning champion and world No 1 Aryna Sabalenka will play Amanda Anisimova in the US Open final after the American ended the run of Japanese star Naomi Osaka on Thursday.
Sabalenka overcame Pegula 4-6, 6-3, 6-4 in a re-run of last year's final and is seeking to become the first player to successfully defend the title in New York since Serena Williams in 2014.
The 27-year-old from Belarus is through to her third successive US Open final.
"It was a really tough match – she (Pegula) played incredible tennis as always and I had to work really hard to get this win," said Sabalenka.
"Just super happy to be back in the final and hopefully I can go all the way again."
Sabalenka has now made the final at four of the last five Grand Slams but has not added to her haul of three majors since winning the 2024 US Open.
She finished runner-up at the Australian Open and Roland Garros earlier this year.
"I badly wanted to give myself another opportunity, another final, and I want to prove to myself that I learned those tough lessons and I can do better in the finals," added Sabalenka.
She landed the first blow in the sixth game against Pegula, who saved a pair of break points before the Belarusian's persistence paid off as she surged into a 4-2 lead.
A sloppy service game from Sabalenka allowed Pegula to respond immediately. The American then held to level at 4-4 and put the pressure right back on the top seed.
An error from Sabalenka gave Pegula another break for a 5-4 advantage and she served out to love to take the first set, to the delight of the Arthur Ashe Stadium crowd.
Sabalenka reset though and roared back to reel off the first three games of the second set, an early break the difference as she sent the match to a deciding set.
A break to open the third set saw Sabalenka edge 2-0 ahead. She scrambled to save three break points and stay in control at 4-2 in and fought off another in the eighth game to close in on victory.
Pegula held and forced Sabalenka to get over the line on her own serve. She eventually converted a third match point with a crunching forehand winner to her palpable relief.
"It was too good from her today at some points," said Pegula.
WIMBLEDON REMATCH IN FINAL
Sabalenka will try to avenge her Wimbledon semifinal loss to Anisimova on Saturday.
The eighth-seeded Anisimova reached her second major final in a row after rallying to overcome Osaka 6-7 (4/7), 7-6 (7/3), 6-3 in a match that stretched well past midnight in New York.
"I wasn't sure I would make it past the finish line. I tried to dig deep. It was a huge fight out there," said Anisimova.
"It means the world. I'm trying to process that right now, it's a dream come true. The hope is to be the champion but I'm in the final now and I'm excited."
Osaka, seeded 23rd, was enjoying her best Grand Slam run since winning her second Australian Open title in 2021 – the last of her four major crowns.
She looked on course to go a step further after taking the first set in a tie-break, boasting a 26-1 record at this level when doing so.
Four breaks in six games to begin the second set betrayed the nerves on both sides.
Anisimova broke for third time to go 5-4 up, but as in the previous two instances then lost her own serve, double-faulting to keep Osaka in the set.
In a reversal of the first tie-break, Anisimova took charge of the second to level the contest.
Anisimova carried that momentum into the decider and broke for a 3-1 cushion as she continued to punish Osaka's ineffective second serve.
Two comfortable service games moved Anisimova 5-2 clear. Osaka held before the American earned two match points in a dramatic final game.
Osaka saved both and carved out two break points only for Anisimova to cut short the comeback and secure victory at the third attempt.