Third seed Halep beats second seed Pliskova 6-4 3-6 6-3
Ostapenko beat Bacsinszky 7-6 (7-4) 3-6 6-3 in first semi-final
Ostapenko becomes first unseeded player to reach French Open final since 1983
Listen to online-only radio commentary of second semi-final
*Halep 4-3 Pliskova
Short and sweet. That's what Pliskova needs these points to be. When she gets embroiled in a baseline slug-fest then it is Halep who is going to be the last woman standing more often than not.
That proves to be the case as a couple of longish points end in the Romanian's favour, but Pliskova digs deep to force deuce and then protects her serve with an ace.
Image source, AFPHalep 4-2 Pliskova*
All looking pretty comfortable for Simona Halep in this first set. The Romanian third seed has a win percentage of 87% on her first serve so far, Pliskova struggling to make an inroads as Halep holds to 15.
Image source, Getty Images*Halep 3-2 Pliskova
More pressure on the Pliskova serve. Halep doesn't let up on her opponent, bringing up another chance as she goes for the double break.
But a stray backhand lets the Czech off the hook and Pliskova takes advantage to hold.
Image source, ReutersHalep 3-1 Pliskova*
Before this year, Pliskova had never gone past the second round at Roland Garros. So it's fair to say this isn't her favoured surface.
The Czech's footwork isn't the best on clay, meaning she hopes to keep the points short and sweet.
Halep, however, has other ideas. One of the great defenders in the women's game, the Romanian keeps batting back at Pliskova in a slog of a hold.
Pliskova sees a break point disappear when Halep cracks a forehand winner, then is eventually ground down after deuce number four.
Image source, Getty Images*Halep 2-1 Pliskova
In fairness to those who are not back in their seats, they might have decided they need a break from the blazing Parisian sun.
However, it means they have missed the first break of serve in this second semi-final.
Pliskova makes two double faults in her second service game, and Halep does not need asking twice to snap up the advantage.
Image source, Getty ImagesHalep 1-1 Pliskova*
The quick turnaround after Jelena Ostapenko's win has caught quite a few of the French fans. Many have nipped out, presumably for an early-evening beverage, and not so many have returned.
Simona Halep doesn't find it tough to get herself motivated in a sparsely-filled arena though, matching Pliskova with a morale-boosting opening hold.
*Halep 0-1 Pliskova
What's Romanian for 'Yeee-haw"?!
That patriotic bloke - and Simona Halep, of course - might be doing a bit of that later on tonight.
First, the third seed - long considered by many to be the favourite to lift the Coupe de Suzanne Lenglen - has to beat Karolina Pliskova.
Blimey, they haven't messed about, They're already out on Chatrier!
And the Czech second seed kicks off proceedings with a neat hold. The crowd ain't seen many of them today...
Image source, Getty ImagesHalep v Pliskova
Piers Newbery
BBC Sport at Roland Garros
You can tell we're getting to close to trophy time, even the ultra-chic French Open is infiltrated by national dress. Romanian Halep fans currently leading the way.
Image source, .
BBC Radio 5 live sports extra
You will be able to listen to the second one between Simona Halep and Karolina Pliskova online.
Ostapenko 7-6 (7-4) 3-6 6-3 Bacsinszky
Russell Fuller
BBC tennis correspondent at Roland Garros
A photo has been doing the rounds of Ostapenko pictured in fellow Latvian Ernests Gulbis' players' box on his run to the semi-finals in 2014. She has come a long way in three years...
Fearless until the end, and a very worthy finalist. Saturday wouldn't be a bad time to win the first tour level title of her career.
Image source, TwitterOstapenko 7-6 (7-4) 3-6 6-3 Bacsinszky
Hit and bust indeed, John Michael.
The hit... Ostapenko cracked a forehand winner on a match point - her 50th winner of the match. That was more than double the number provided by Bacsinszky, who hit 22.
The bust... the Latvian also made 45 unforced errors, again twice Bacsinszky's tally (19).
#bbctennis
John Michael Poole: She's some player is Ostapenko! Love the hit or bust nature of her game
Ostapenko 7-6 (7-4) 3-6 6-3 Bacsinszky
Image source, AFPOstapenko 7-6 (7-4) 3-6 6-3 Bacsinszky
Jelena Ostapenko's march to the Roland Garros final can be contextualised by some fascinating facts.
Ready for a few?
Image source, EPAOstapenko 7-6 (7-4) 3-6 6-3 Bacsinszky
Jelena Ostapenko on reaching her first Grand Slam final : "I always play aggressive and I was always trying to hit the ball when I had a chance. That helped me win today.
"I love playing here, thanks for coming, I'm just happy with the way I celebrated my birthday!"
Image source, Getty ImagesOstapenko 7-6 (7-4) 3-6 6-3 Bacsinszky
What were you doing on your 20th birthday? Getting plastered in a dodgy nightclub somewhere?
Jelena Ostapenko is being serenaded by former WImbledon champion Marion Bartoli on Chatrier with a rendition of 'Happy Birthday'.
Where's the cake?!
Ostapenko 7-6 (7-4) 3-6 6-3 Bacsinszky
She's done it! Jelena Ostapenko is the first unseeded player to reach the Roland Garros final since 1983.
Some of you lot probably weren't even born. The 20-year-old Latvian certainly wasn't!
Image source, ReutersOstapenko 7-6 (7-4) 3-6 5-3 Bacsinszky*
Make that two match points away from her first Grand Slam final...
Ostapenko 7-6 (7-4) 3-6 5-3 Bacsinszky*
What Timea Bacsinszky can take comfort from is the fact that Jelena Ostapenko has lost serve more times than she has held it in this match.
Oh...
Out of nowhere, the unseeded Latvian finds her service game - and holds to love.
She is one game away from her first Grand Slam final...
*Ostapenko 7-6 (7-4) 3-6 4-3 Bacsinszky
Russell Fuller
BBC tennis correspondent at Roland Garros
Ostapenko hit her 240th winner of the fortnight midway through the sixth game of this deciding set. Believe me, that is a mind boggling number.
She is the more vocal of the two players on the court and what everyone is now wondering is whether all out attack is going to see her into a first Grand Slam final on her 20th birthday?