The No. 6 seeds comes back from down a set and a break to advance to her first career Grand Slam final. She'll face No. 2 seed Aryna Sabalenka on Saturday.

After Muchova's racket fling, Pegula wins the next two points to hold serve and move one game away from the win. She's played more conservatively this set, letting Muchova go for the winners, and the errors that come with them.

Muchova is pushing to even the match, but another missed break point left her so frustrated she tossed her racket in the air at the end of the point. Fortunately, she also caught it.

At age 30, Pegula is two games away from her first career Grand Slam final.

We've gone full reverse here. Pegula takes a significant lead in the third set and Muchova is now yelling at her box. Now it's Muchova who needs to make an adjustment.

After going down a set and a break, Pegula fights back to even the match and send it to a winner-take-all third. She looked much better in that set, especially after the first couple games, but was also helped by 19 unforced errors from Muchova in that frame. She's still not winning her first serve enough, taking 13 of the 24 points in that set, but she managed to punish Muchova's second serve (12-of-15 points won).

This will be Pegula's first three-set match of the tournament.

This has been an eventful second set, as Muchova prevents Pegula from consolidating the break. She also seems to be reaching for her side a bit, so she might be dealing with something.

That was a big one. After four deuces, Pegula gets her second break and is now on track to even this match. She looked completely down just a few games ago, but is now pumping her first and yelling. This would be quite a comeback.

Finally. It wasn't the best showing for Muchova, but Pegula is back in this match.

All she did was hold serve, but even that feels significant for Pegula at this point. She had to hold off a break point in the process. Stark stat: she has won 10 of her 22 first-serve points so far. Muchova, meanwhile, has won 15 of 19. If Pegula doesn't figure out how to change both in her favor, this is basically over.

It's all Muchova now. She's won all eight points at the net and is still showing a clear advantage in baseline rallies. Pegula's body language is not encouraging and she is going to need quite a reversal.

The New York City crowd is doing its best to lift up the lone American left in the women's field, giving her a nice cheer on her first point won in the second set.

That was easy, at least after the break points. Muchova was all over the court, feasted on both Pegula's first and second serves and threw down 11 winners to Pegula's three to convincingly take the first set. If Pegula doesn't get back up to speed, we're looking at a sub-hour match.

The Czech veteran is looking sharp so far, or at least sharper than Pegula, who committed three unforced errors and basically handed away a game she needed to win.

Tied 1-1, Muchova fought off three break points to hold serve in a marathon game. There were some pretty great points in that.

Two unforced errors from Pegula, let's see how she responds.

Two players who have dealt with injuries for most of the year, now playing for their first US Open final. Pegula is a -155 favorite on BetMGM.

Emma Navarro put up an incredible fight in forcing the second set to a tiebreaker. From there, however, Aryna Sabalenka put up a wall, winning 8 of 10 points and righting herself after getting frustrated from being unable to put Navarro away.

Navarro had to play catch-up throughout the entire match and it ultimately caught up with her. Sabalenka advances to her second consecutive US Open final.

Just as the set appeared to be slipping away for Sabalenka, she rights herself with a blistering return that Navarro can't get to, despite her best effort. She needed that one.

We're at a 6-6 tiebreaker. Agility versus power.

An inability to put Navarro away is frustrating Sabalenka. As a result, she's getting sloppy and hitting balls into the net.

At the moment, Sabalenka doesn't seem to have answers and is looking to her coaches for help. Meanwhile, Navarro is gaining steam and the crowd is giving her energy as she takes a 6-5 advantage.

We've said this already. but this match isn't over yet. Just as it looks like Aryna Sabalenka is ready to put Emma Navarro away, the American fights back and holds. We're at 5-5 in the second set and the crowd is getting louder.

Emma Navarro isn't going away. Just when it looks like Aryna Sabalenka will flex and finally dispatch her opponent, Navarro fights back. She's hanging on, yet isn't letting go either. That tenacity is keeping her in a match that it looked like she might quickly lose.

Just as it looked as if Sabalenka was going to assert herself on her way to winning the second set and the match, Navarro fights back to close to within 4-3 and stay alive. This isn't over yet.

Trying to maintain her footing while moving quickly side-to-side caused Navarro to slip and scrape her right knee. While that may not be inhibiting her physically, it shows how Sabalenka is battering her across the court.

Navarro takes a 2-1 lead in the second set. Her quickness all over the court, catching up to virtually everything Sabalenka is offering has her back in this match. Navarro caught Sabalenka flat-footed, unable to move to her right in time to get to her return.

Navarro is hanging in there, but having to keep up with Sabalenka's power appears to be wearing her down. Sensing that she needs a boost, the crowd at Arthur Ashe Stadium is cheering her on. But Navarro has to do something to break up Sabalenka's rhythm here. She is controlling the pace.

Aryna Sabalenka made pretty short work of Emma Navarro in winning the first set, 6-3. With a powerful serve and return, Navarro had to play back to keep up.

Though she played great defense moving laterally, Sabalenka countered with drop shots that Navarro couldn't catch up to. The power plus the well-placed finesse is a formidable combination that Navarro seemingly can't answer.

Sabalenka shows that she's not just power, dropping a touch shot that Navarro can't catch up to toward the net. 5-2 in the first set.

Navarro's lateral movement is keeping her in this match. Sabalenka keeps hitting the ball hard, thinking she's got a point. But Navarro gets in position to make a return consistently. Can she keep up this defense throughout the match?

As Pam Shriver pointed out on the ESPN telecast, Aryna Sabalenka sometimes gets surprised when there's a return on her serve or forehand. She ends up watching the power of her serve and doesn't gather herself for the return. Emma Navarro isn't backing down.

However, Sabalenka is ahead 3-2 in the first set.

Again, Navarro is standing firm early on, not getting overmatched. She's on serve again with the crowd at Arthur Ashe Stadium supporting her. 2-1 in the first set.

As she has through the US Open – and Wimbledon before that – Emma Navarro has kept her cool and remained calm through Aryna Sabalenka's onslaught. But Sabalenka is overpowering early on.

Aryna Sabalenka showing her power early on, serving and returning shots that Emma Navarro hasn't been able to return. She's taken the first two points in their opening game.

Emma Navarro advanced to Thursday's semifinal by defeating Paula Badosa in straight sets on Tuesday, rallying from a 5-1 deficit in the second set. She's one of two Americans in the semifinal, joining No. 6 seed Jessica Pegula.

Aryna Sabalenka reached her fourth consecutive US Open semifinal with a win over No. 7 seed Zheng Qinwen in straight sets.

Among the celebrities attending festivities in Flushing Meadows tonight are Maria Sharapova and Billie Jean King. "Good Morning America" co-host Robin Roberts and TV mega-producer Shonda Rhimes are also on the scene.

Tonight's first US Open women's semifinal between No. 13 Emma Navarro and No. 2 Aryna Sabalenka is the third time these two have faced each other this year,

In March, Navarro won the first match at Indian Wells in three sets. Sabalenka was victorious at the French Open, winning in straight sets.