Ostapenko wins 4-6 6-4 6-3 to win the French Open
Third seed Halep won the first set 6-4 at Roland Garros and was 3-0 up in the second
Ostapenko, 20, fought back in the second to win it 6-4 and force a deciding set
Halep, who would have become world number one with a win, threw away a 3-1 advantage in the final set
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*Halep 6-4 4-6 3-3 Ostapenko
More pressure on the Ostapenko serve. Halep takes the game into deuce, only to see the young Latvian stick her foot down on the pedal. Hard.
Ostapenko cracks down a 110mph ace that leaves Halep swishing at warm Paris air, then hammers a double-handed backhand cross-court to safety.
Image source, AFP#bbctennis
OnsideVIEW: Brilliant final. One of the best in recent years. Stan and Rafa have a lot to live up to.
Halep 6-4 4-6 3-2 Ostapenko
Simona, Simona, Simona...
The Romanian has the match on her racquet, but rather like the second set, she gets the jitters. A forehand winner from Ostapenko wipes out Halep's break to the delight of the Chatrier crowd, which is getting right behind the world number 47.
They don't want this to end. We all don't want this to end! On we go...
Image source, AFP*Halep 6-4 4-6 3-1 Ostapenko
There you go. Three sloppy unforced errors from Ostapenko gift three break points to Halep.
The Romanian has been guilty of wasting her chances today, failing to take eight of her previous 14 break points. Make that nine of 15...
But then she keeps her nerve to take the next one - she's in control.
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Clare Lickley: Definitely need more younger tennis players like Ostapenko It's so inspiring to see! But what an intense final.
Olowoyo Olusegun: Dont know where this game is going but Ospapenko is really making it interesting. One set apiece.
Image source, EPAHalep 6-4 4-6 2-1 Ostapenko*
Solid hold from Halep. She needs them. Because you still feel Ostapenko has got a dodgy service game in her...
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Clare Lickley: I hope that Jelena Ostapenko wins because she deserves it! Amazing talent and worked so hard to get to the Roland Garros final.
*Halep 6-4 4-6 1-1 Ostapenko
An interesting stat shows us how Ostapenko's power is hurting Halep. The Romanian third seed, who will rise to number one in the rankings with a win remember, has been pinned back so much that she only spent 1% of the second set rallies inside the baseline.
Ostapenko cruises to a hold, an ace sealing the deal.
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Jide Yusuf: Can this drama be prolonged for tennis fans' sake? Good for female tennis! Come on Jelena.
Shambhav Joshi: What grit shown by Ostapenko. Her winners are brilliant to watch.
Jonathan Hextall: 6-4 3-0 and one hand on the trophy. Halep needs to dig deep and regroup now.
Halep 6-4 4-6 1-0 Ostapenko*
Turning point? Halep is staring a break in the face, when she wallops a fetch of a forehand back across the net.
Ostapenko lies in wait at the net, decides to leave it... and it hits the line! That gives Halep the momentum to go on and win the next two points. Big hold.
*Halep 6-4 4-6 0-0 Ostapenko
Piers Newbery
BBC Sport at Roland Garros
The first set finished with Ostapenko's 23rd error and an angry swipe of the racquet, the second with her 36th winner and arms aloft as though in victory. There isn't much in between with the Latvian, and her remarkable run could yet end with her holding the trophy.
Halep needs to change something or she will get swept away, and coach Cahill stands throughout the changeover, possibly attempting some form of telepathic communication.
Halep 6-4 4-6 0-0 Ostapenko
What do we want? A decider!
When do we want it? Now!
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James Stevenson: Stunning shots from Ostapenko. That forehand on the run down the line!
Halep 6-4 4-6 Ostapenko
Wow. Just...wow. If drama and entertainment is what you're after then you're in the right place.
Ostapenko has the Chatrier crowd on their feet with a pair of forehands winners down the line, and they barely have time to stop clapping before the unseeded Latvian takes set point.
Image source, EPAHalep 6-4 4-5 Ostapenko*
Camille Pin
Former tour player on BBC Radio 5 live
How tough is this for Halep? She's down and negative in her body language. She's got an opponent who is difficult to deal with. You never know what she's going to do.
Mentally, she's tired and if you add in the pressure of winning the title at the end of it, it's hard.
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Clare March: This final is crazy, but very entertaining.
Halep 6-4 4-5 Ostapenko*
This is bordering on ridiculous now. Simona Halep might as well have warmed this up and grabbed a knife and fork. She hands it on a plate.
An unforced error sets the tone as Ostapenko goes on to crack a forehand winner for 30-0, another big return being, well, unreturnable and it is a hold to love.
Jelena Ostapenko is serving for the second set...
*Halep 6-4 4-4 Ostapenko
Yet again Ostapenko's break is not backed up by a hold. This match has more ups and downs than a day out at Alton Towers.
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Ian B: What a breath of fresh air Ostapenko is, so much talent, world at her feet.
Image source, EPAHalep 6-4 3-4 Ostapenko*
I mean, we shouldn't be that surprised. Ostapenko did fight back from 5-0 in the first set to win against Caroline Wozniacki. That's former world number one Caroline Wozniacki...
Image source, EPA