Live Commentary: Serena Williams vs. Timea Bacsinszky - as it happened

Hello, and welcome to Sports Mole's live coverage of the French Open semi-final between Serena Williams and Timea Bacsinszky.

After witnessing Lucie Safarova tough out a gruelling win over Ana Ivanovic, Serena Williams will be intent of making lighter work of Timea Bacsinszky in this second semi-final but the Swiss player is sure to have something to say about that. She's a huge underdog but she will acknowledge that she has nothing to lose in what is undoubtedly the biggest match of her career.

We look ready to get started on Philippe Chatrier with both warmups having been completed. It will be Serena to serve first.

Williams begins the match with a backhand error but a massive first serve down the middle sees her back on level terms. She takes the following three points in emphatic style and it's a strong hold to start this semi-final.

The early danger signs are there when Williams eases into a 0-30 lead but Bacsinszky remains composed to get to deuce. She then finds her way to game point before Williams makes a glaring forehand error to allow the Swiss to get on the board.

There have reportedly been a few concerns regarding Williams's fitness in the build-up to this match but she looks comfortable enough in hitting her way to a love hold. It should suit her serving first because if she can remain ahead, the pressure will always fall on Bacsinszky's shoulders.

A baseline from Bacsinszky tells Williams that she has settled into this match, but at 30-15, she gets over ambitious with a drop shot and the world number one is back to 30-30. She holds her nerve though as she crushes a forehand winner and an ace to take the game.

BREAK! Williams looks a little vulnerable here after being overpowered by the 25-year-old but after falling 0-30 behind, the American finds two huge first serves. However, Bacsinszky is playing some unbelievable tennis, and after hitting a first-serve return winner to save a game point, she takes the next two points with a lob and a cross-court backhand to seal the first break of the match. We could have a game on here.

At the change of ends, Williams is covering her neck in ice. She doesn't look well at all. She takes the opening point of the sixth game but Bacsinszky comes roaring back with a forehand winner down the line on the way to two game points. She only requires one after catching the line with another aggressive baseline shot and she looks in the groove here.

Williams starts the next game with an ace but Bacsinszky shows her confidence by plucking the ball out of the air to convert a drive volley. She holds comfortably enough though, but she's hardly sprinting back to her chair.

After the opening two points are shared, Bacsinszky controls the next rally before forcing her opponent into the error. The Swiss then hits the way to the next two points to leave Williams having to serve to remain in the first set.

Serena's her usual self when she has the ball on her racquet but she looks so lethargic. She doesn't have to do any running to open up a 40-0 lead but she allows Bacsinszky to remain in the game as soon as the rally is extended past a few shots. Another Bacsinszky winner takes her back to 40-30 but Serena gets the hold when her opponent sends a second-serve return wide.

SET! Bacsinszky takes the first point when Williams blasts a return long before the Swiss catches the line to register an ace out wide. She has half a chance for 40-0 but she miscues a forehand to give Williams hope, but the American proceeds to net with a forehand on the next point to give Bacsinszky two set points. They are both saved though as Serena goes big with a forehand before Bacsinszky misses out with a forehand. It's break point for the world number one but it's an outstanding save from the underdog, who finds the target with a backhand winner. Williams is fighting hard but she can't deny her opponent, who takes the set when the world number one misses out with a forehand.

It's worth noting that Serena looked better in that game but she has a mountain to climb if she is going to overcome Bacsinszky, who isn't playing like someone who is competing in their first Grand Slam semi-final.

Serena still looks sluggish but she at least held serve with relative ease. I don't think that there is any danger of her pulling out. She will understand that Bacsinszky will feel the tension as she looks to make her first final.

Bacsinszky opens up a 30-15 lead but Williams levels things up with a backhand return winner. It's a bizarre reaction though. She looks like she has nothing left. Far from it, but she is on the wrong end of a net cord and Bacsinszky is able to seal the game.

I'll tell you something, Serena is far from done in this match. At 30-0, she makes plenty of ground to stretch to make a drop shot before catching the baseline to record the winner. It's a remarkable shot. She then crushes a baseline winner for the love hold and Bacsinszky has something to think about.

Williams gets into position for two routine put-aways but she misses both, much to her frustration. It gives Bacsinszky the momentum to come through with a love hold of her own.

BREAK! Out of nowhere, Williams drops to 0-30 after two unforced errors before she remains competitive with an ace down the middle. Bacsinszky feels hard done by when she's on the wrong end of a questionable line call, but she shakes it over to drill a backhand winner down the line to earn a break point. Williams saves it, as well as denying Bacsinszky on four more occasions, but the Swiss is unnerved and after middling a backhand return, she benefits from a mistake from Williams to break through.

BREAK! That game looks to have taken a lot out of Serena's legs and she wastes little energy on the first two points which bring mixed results. However, she gets into the next two rallies and the errors come from Bacsinszky, and the break is sealed with a brilliant backhand return.

Back comes Bacsinszky who takes the opening point, but Williams is unmoved as he fires down successive aces on the way to a comfortable hold. Important game on its way for Bacsinszky.

BREAK! Bacsinszky looks relatively comfortable at 30-15 but a double fault and forehand error later and she's staring at a break point. She gets into the next exchange but Williams is too strong and puts away the drive volley at the net.

SET! This is slowly turning in the favour of Williams and although she wastes two set points, she takes her third opportunity to level the match. If she can last the pace, there is only one winner from here.

BREAK! Bacsinszky shakes off the disappointment of losing that set by taking the first two points of the third set, but the American replies with two venomous winners to get back to 30-30. Bacsinszky should win the next point but she goes for too much on a simple forehand and this is Serena's chance to break. Unbelievably, Bacsinszky misses another sitter on her forehand and she is broken. It's a terrible way to lose serve.

It's a sensational response from Bacsinszky who brings up two break-back points but Williams shows the resilience of a champion by connecting with an ace and backhand conversion at the net to hold onto her serve. Big moment.

BREAK! This has turned into a must-hold game for Bacsinszky but she finds herself 15-30 down after missing with two forehands. She then hooks a forehand miles long of the baseline and this is slipping away fast. Or is it? Bacsinszky saves them both before finding the line for an ace. However, she can't get over line and Serena comes roaring back to take three successive points and open up a considerable lead.

You feel as though Bacsinszky needs to break straight back to have a chance in this match but Serena is striking the ball as cleanly as she has all match and the Swiss has no answer. She holds to 15 thanks to a backhand winner into the open court and she is closing in on a place in the final.

BREAK! Bacsinszky looks almost beaten and two weak shots from the baseline hand Williams a 15-30 advantage. The world number one crushes a backhand winner down the line for two break points before she repeats the trick off the opposite wing to move within touching distance of a showdown with Lucie Safarova.

MATCH! Williams moves 15-0 ahead after a forehand error from the Swiss before she shows that she actually has a bit of energy left with the shot of the match, a cross-court forehand that left Bacsinszky stretching for thin air in the centre of the court. She follows that with a big first serve for three match points but Bacsinszky shows heart in prevailing from a baseline exchange to save the first. She can't save the second after drilling a shot long and Serena records her 10th successive game to book her place in Saturday's final.

At one point, it looked questionable whether she would complete the match, but that she did and Serena Williams has earned her place in the French Open final. Timea Bacsinszky deserves so much credit but as soon as the world number one appeared over her health issues, there was only going to be one winner. She will play Lucie Safarova in the final.

That will be all from Sports Mole this afternoon. Thank you for joining us and we hope to see you again for Saturday's final. Goodbye for now.