Aryna Sabalenka waited until the last possible moment to wake up in the US Open semifinal on Thursday, but all that meant was style points in the end.

The No. 2 seed overcame a slow start to defeat No. 19 Madison Keys 0-6, 7-6 (7-1), 7-6 (10-5) at Arthur Ashe Stadium and advance to the second Grand Slam final of her career. She will face No. 6 seed Coco Gauff, who beat Karolina Muchova earlier Thursday, in the final on Saturday.

For the first 14 or so games, Keys appeared to be coasting to a shockingly dominant upset of Sabalenka. She hung a bagel on her in the first set and went up a break three games into the second, putting her in position to reach the final just be holding serve.

She got there with an impressive showing in the return game against Sabalenka, who entered the match second in the WTA in service games won. Sabalenka is one of the fiercest servers on tour, but Keys took 14 of her 21 service points in the first set to set the tone.

Sabalenka, the tournament favorite following the upset of No. 1 seed and defending champ Iga Swiatek, had been looking like the most dominant player of the tournament entering Thursday, winning every match in straight sets. Only one of those sets saw her opponent win more than three games.

She wasn't looking so dominant midway through the second set, except against her racket as she berated her team in the stands following a lost game.

"They're not my team anymore, I fired them," Sabalenka joked to ESPN after the match, under happier circumstances.

Sabalenka picked the last possible moment to wake up. Down 5-4 in the second set with Keys serving, Sabalenka scored her first break of the game, though she was helped by two unforced errors and a double fault by Keys. One held serve later, the two were playing a tiebreak, which Sabalenka won easily.

The third set began on serve until Keys broke Sabalenka to go up 4-2, then got broken back immediately. Keys very nearly grabbed another break the next game, but Sabalenka saved two break points to stay alive and push the score to 4-4. A few minutes later, the match was heading to its second tiebreaker.

Once more, Sabalenka cruised to a tiebreak win and finished off perhaps the most stunning comeback of her tennis career. In fact, she got to celebrate the win twice, as she dropped her racquet and covered her mouth thinking she had won after going up 7-3, not realizing the US Open's third-set tiebreakers go to 10 points.

Then her team gave her the bad news.

Five points later, Sabalenka was celebrating for real.

Aryna Sabalenka vs. Coco Gauff should be a fun one

By virtue of Swiatek's loss in the fourth round, Sabalenka is already assured the No. 1 ranking with the WTA after this tournament, but she'll obviously want more.

The Belarusian has been the most consistent player in tennis this year, winning the Australian Open and reaching the semifinal in the two other Grand Slams while also reaching the final at Indian Wells. She has also reached the US Open semifinal in each of the last two years, but only broke through to the final this year.

With Gauff, she faces a teenager who has been earmarked for stardom since she reached the fourth round of Wimbledon at 15 years old in 2019. Now 19, a win for Gauff would make her the 11th teenager in history to win a Grand Slam.

It will not be an impartial crowd at the final on Saturday.

"She's an unbelievable player, she's doing really incredible things here at the US Open," Sabalenka said. "Yes, the crowd will be supporting her a lot. I mean there's something I expect. This is nothing crazy. I'll just go there and and do everything I can. I'll be there. I'll be fighting for every point. I'll do my best."

Sabalenka and Gauff have faced each other three times, with Gauff holding a 3-2 edge. Their most recent meeting was at Indian Wells this year, with Sabalenka winning 6-4, 6-0.