A rare drop shot from Pegula draws Sabalenka to the net - but the American gets the follow up passing shot all wrong.

It's details like that which can define a Grand Slam, and Sabalenka is getting the better in the clutch moments so far.

She holds to 15.

Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2

Sabalenka is playing like a woman who is possessed. There is fear in her eyes.

Her facial expressions were just fear and terror for most of the back end of that set and somehow that just got to Pegula. That was breathtaking stuff.

It was like the more possessed Sabalenka looked, the harder she was hitting.

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The US Open is this year offering the biggest prize fund in Grand Slam history with a total of $108m (£79.2m) up for grabs - marking a 20% increase on last year.

The singles' champions will receive $5.5m (£4.03m) each in a 10% increase on 2025.

First set point, saved by Pegula with a powerful forehand.

Second set point, taken by Sabalenka with a huge forehand deep that Pegula, backpeddling, can only put into the net.

When she needed to, Sabalenka raised her game to devastating effect.

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Hmmm. A loose forehand wide from Jess Pegula, and she's 0-30 down. The crowd responds with encouragement.

But a limp 94mph second serve is dismissed by Sabalenka, giving her three set points...

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Aryna Sabalenka places a towel over her head at the changeover. Trying to block out the distractions. She knows a break here would be huge in the context of the match.

Jess Pegula to serve as she tries to take the first set to a tie break.

Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2

I think Sabalenka's body language and behaviour right now is questionable. I think it is unnecessary with what we are witnessing and the level of tennis.

She feels like she is playing badly and she is not. I think her body language is making her miss.

She is tormented and stressed. She is every adjective you can imagine apart from composed right now.

The more Sabalenka gets irritated, the more the home crowd will get behind Pegula and on the back of the top seed.

But the scream of frustration is from Pegula this time, as she drops an easy shot into the net.

Better from Sabalenka, who holds to 15.

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Can Pegula hold serve? Yes She Can.

She holds to 15, with Sabalenka visibly annoyed as she continues to overhit many of her ground strokes - before chucking her racquet to the ground as Pegula confirms the hold.

Sabalenka's body language is not inspiring confidence at this stage.

Huge cheers from the crowd as former First Lady Michelle Obama is shown on the big screen.

She will hope to watch fellow American Jess Pegula serve to stay in this first set.

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Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2

That is two points in the game where Sabalenka should have won the point. She was in the driving seat but she just over-cooked that forehand. She looks so disappointed.

Sabalenka is behaving like this is a terrible set and yet the standard has been so incredibly high. If she is not careful these emotions are going to get the better of her.

What a time for Aryna Sabalenka to throw in the first double fault of the match!

Advantage Pegula for the first time, her first break point, and a huge cheer from the crowd... until she is forced wide by another booming serve and Sabalenka saves the break into the open court.

Sabalenka moves to advantage with an overhead winner at the net, and sees off the break threat with another unreturnable serve.

Aryna Sabalenka clearly outguns Pegula in terms of power - four aces, 11 winners and a good record on second serves.

But whenever she is taken to a rally, Sabalenka is being outplayed by Pegula. Case in point here as Sabalenka puts one in the net, it's 30-30 on the top seed's serve and the American crowd is roused.

Sabalenka responds with another 117mph serve, nothing anyone can reasonably do against that.

But then, after another rally, Sabalenka goes long. Deuce, and half a chance for the third seed...

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This is the first time the top-four ranked players have reached the women's semi-finals at any Grand Slam since Wimbledon in 2009, and it hints at a shift away from the unpredictable landscape that has characterised the women's game in recent years.

Since the start of 2020, there have been 13 different Grand Slam women's singles champions - compared to just seven on the men's side.

But the big names are all here, so after top seed and two-time defending champion Aryna Sabalenka faces Jessica Pegula, Elena Rybakina - who will replace Sabalenka as the new world number one on Monday - takes on fourth seed Coco Gauff afterwards.

Both women are getting more than 75% of their first serves in, and averaging over 100mph. We have not had a single double fault yet.

It is really helping add to the high quality we have seen so far in this match.

Pegula maintains that theme with a hold to 15.

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Annabel Croft
Former British number one on BBC Radio 5 Sports Extra 2

There is a self-assured feeling with the way Pegula is playing this match at the moment. She looks very at ease and looks like she is playing within herself and yet, this is the highest level I have seen her play at.

She is just serving better than I have ever seen.

Aryna Sabalenka is hitting her serves with immense power tonight. She's up to four aces already, with an average speed of 105mph.

When she doesn't get the first serve in, Pegula is dealing well with her power on court. But Sabalenka does enough to hold to 30 again.

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