Rybakina beats Pegula in three sets - The first semi-final of the WTA Finals saw Elena Rybakina see off Jessica Pegula 4-6 6-4 6-3

Her booming serve wrests control in the game and Pegula has no answer to it.

The American sends a backhand return just wide to put the Kazakh star into Saturday's final.

A fine rally ends with a fantastic backhand from Rybakina but it looks like Pegula gets a kind call on a ball which seemed long to send it to 40-15.

A net chord changes the course of the game and Rybakina battles back to deuce and Pegula sends a forehand long and drops her racquet to the hard court in frustration.

She then puts a forehand into the net for back-to-back unforced errors to give Rybakina the chance to serve for the game.

Rybakina commits to the net but hits a loopy forehand and Pegula takes her time before hitting down the line for a 0-30 lead.

The American forces her opponent deep and an error gives her three break-back points.

Rybakina saves one with a stooping backhand, but a long forehand cedes her serve. What a game this is.

Pegula under pressure as she is punished for a short groundstroke down the middle which Rybakina dispatches to take a 0-30 lead.

A long forehand gives Rybakina two break points but Pegula brings out her first ace of the match before the Kazakh star forces the American deep and into an error.

We are in a pattern of service games being won fairly comfortably.

The game is won with a wide serve which Pegula cannot get back in play.

Pegula with a dominant service game with Rybakina frustrated at not being able to set herself for her big shots.

A long forehand brings the match to 2-2.

Back-to-back unforced errors from Rybakina brings the score back from 30-0 to 30-40.

Rybakina saves break point as Pegula just manages to get a serve back and the return is easily dispatched but another loose shot sets up another chance for the American.

Once more Rybakina saves it and goes on to hold serve.

Pegula responds strongly, despite Rybakina forcing her back early and winning a point with trademark booming forehand, the clever American maintained the advantage through the rest of the game.

The tide seems to have turned.

Rybakina wins the serve to love, including her eighth serve of the match.

After losing the first point, Pegula wins a battle of cross-court backhands to avoid a 0-30 hill to climb.

Rybakina brings up her 46th unforced error during the game.

The American follows up a big first serve with a forehand winner, but sends two backhand into the net to give Rybakina set point but the Kazakh sends a forehand long.

A poor forehand into the net sets the American up with game point but the shot of the match with a cross-court forehand past Pegula looking to volley at the net brings up deuce again.

Eventually a too-deep forehand from Pegula gives up a second set point and Rybakina smashes a cross-court backhand to take the lead.

The Kazakh's serve earn her two cheap points, but good deep groundstrokes from Pegula put pressure on and bring the score back to 30-30 and a double fault brings up break point.

Her first serve again deserts her and a fine deep cross-court backhand forces an error with Rybalinka hitting too long. We are back with serve.

Pegula goes 30-0 ahead but a weak backhand into the net then wild attempted cross-court forehand brings the score level.

She recovrs to win the next two points to make Rybakina serve for the match.

Pegula screams in annoyance as he misses a cross-court forehand when she was moving Rybakina around the court.

She has to take advantage of these points as too many Rybakina dominates either with her groundstrokes or serve, which grabs her an ace, then an easy volley winner which moves the Kazakh a game away from parity.

Pegula comes out with a purpose moving Rybakina around the court to seize the advantage in the game.

Rybakina returns just long to give a much-needed easy game win for the American.

Rybakina's booming serve down the centre is proving advantageous, but a double fault brings the scores back to deuce.

She rebounded with a brilliant cross-court winner and then an easy forehand is put into the net by Pegula to give the Kazakh star a 4-1 lead.

Pegula holds her hands up in frustration at her play as two unforced errors leave her 0-40 down.

She then plays a fine inside-out forehand winner but the next point sees her put the ball into the net giving Rybakina a break.

Rybakina had Pegula on the rack on the first point before a huge forehand which went wildly long and left her opponent ducking for cover.

From this point onwards Rybakina dominates the game and the set stays with serve.

Rybakina has come back with a purpose after her slightly prolonged break between sets.

She flexes her muscles with powerful forehands giving her a 0-40 advantage.

Pegula's fine backhand cross-court pulls her back to 30-40 and then a loopy long forehand brings it back to deuce.

A wonderful backhand down the line which Rybakina applauds sets up a Pegula's advantage and she mixes up her serve to wrongfoot her opponent and hold serve. Could be a key game.

Just like in the first set a powerful start from Rybakina as she backs up powerful first serves with groundstrokes to build a 40-0 lead.

A double fault sees it be brought back to 40-30 but then Pegula shoots long then holds her shoulder, but it seems to be more in frustration than pain.

But we are underway in the second set now. Rybalenka serving first.