Olga Savchuk
Ukrainian former player on BBC Red Button

Boulter is trying to get back to how she started the match, but it's not easy. The numbers were slightly better for Pegula in that second set.

Boulter's double faults proving costly at times in set two while Pegula was clinical with her break points.

Boulter fires wide and Pegula, just like Navarro in the previous game, fights back to level things up with victory in the second set.

Can she follow her compatriot to see out victory or will we be heading for a deciding doubles match?

Image source, Reuters

The perfect time to produce an ace as Pegula saves break point.

Boulter gets on the attack at deuce and the American does well to deal with it, eventually forcing the Brit long.

Set point.

Pegula misses the forehand and that brings up a second break point for Boulter.

Boulter can't take advantage of Pegula's second serve, which the American smartly places on Boulter's backhand side.

Deuce.

Boulter responds to a brilliant Pegula serve with an even more brilliant return and she's back in the game at 30-30.

Then the American fires long and all of a sudden Boulter has a chance to stay in this set with a break point.

Too much on the forehand from Boulter hands Pegula a 30-0 lead but a crunching one into the corner gets her first point on the board in this game.

Peter Odgers
BBC Sport commentator

Are we going to go the distance yet again? So many matches have gone to a final set here.

Boulter does what she needs to do and takes the hold to force Pegula to serve out the set.

The American is a game away from levelling this match. Unless Boulter can find something here.

Another hold on the board for Pegula with a brilliant point placed in the wake of Boulter.

That puts Pegula within one game of taking the set and the Brit will have to serve to stay in it.

Olga Savchuk
Ukrainian former player on BBC Red Button

That was a must hold game for Boulter.

Boulter regains some confidence to move to 40-0 on serve but another double fault puts a blemish on what would have been a perfect serving game.

Hold to 15 will do nicely, though.

The errors are starting to creep into the game of Boulter and Pegula holds to love with ease.

Break backed up. Two-game cushion secured.

Pegula was unable to consolidate her earlier break of serve. Can she do so this time?

Peter Odgers
BBC Sport commentator

You have to give credit to Pegula. She'll have been disappointed about that last game, but she's right back at it in the next game.

Boulter skews her backhand wide and there's the break of serve for the third game in a row.

She moves a break ahead for the second time in the set.

Oh no!

A second double fault in the game hands Pegula break point.

Are those old serving problems coming back to haunt Boulter?

What a point! Brilliant touch at the net from Boulter then a backhand smash moves her to 30-15 on serve.

But that's followed by a double fault that offers Pegula a way back into the game.

What a miss! Pegula hangs her head as she misses the backhand while advancing into the net.

And there's the break back for Boulter.

Just as you thought the momentum was shifting over to Pegula.

Image source, Reuter