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 3-4 Ostapenko*
Camille Pin
Former tour player on BBC Radio 5 live
I'm impressed. Ostapenko has no experience but mentally she's capable of never giving up and playing her own game.
Now she's playing great, with more strategy and focus. It's almost like a new match is starting.
Halep 6-4 3-4 Ostapenko*
Well, well, well. If Ostapenko bottled up her fighting spirit and flogged it then they would be queuing up for days in Riga.
Unbelievable. A couple more forehand winners nab the break - the latter going so deep that Halep would need a spade to dig it out.
Ostapenko twirls her hand in the air towards her box, a fist-pump straight from the street. You know what I mean.
Image source, Reuters*Halep 6-4 3-3 Ostapenko
Camille Pin
Former tour player on BBC Radio 5 live
Ostapenko's such a great talent. For the second serve she went to the forehand, which is such a good thing to do tactically.
It seems like when she's down she finds a balance between being aggressive and making her opponent move.
She's still fighting. She never gives up.
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Jonathan Hextall: Halep should win this in two. Long overdue a Grand Slam and this is her best shot.
Image source, EPA*Halep 6-4 3-3 Ostapenko
Every time Jelena Ostapenko has broken Simona Halep's serve, she has failed to back it up with a hold. And as she goes 40-15 down it looks like to be another doomed mission.
Until... the Latvian battles back to save those two break points, forcing Halep behind the baseline and into errors.
What a hold! From a break point away from 4-0 down, Ostapenko is back level.
Halep 6-4 3-2 Ostapenko*
Piers Newbery
BBC Sport at Roland Garros
The Paris crowd is a great one to have on your side, but never take them for granted.
Ostapenko's failure to stay in touch was starting to draw a few collective sighs as this set slipped away, but they leap to their feet and roar as she swats away a forehand to get on the scoreboard and then are back in full "Je-le-na! Je-le-na!" mode as she breaks back. Fickle.
Halep 6-4 3-2 Ostapenko*
OK, I was definitely joking about this being over in 15 minutes.
Halep has not looked comfortable on serve, particularly her second serve on which she has only won five points in the match.
A couple of volleyed winners help Ostapenko tee up a break point... she gets it! Halep gets her strings on a return, but can't direct it to safety.
Now then. Can she back that up with a hold? Hmmm...
*Halep 6-4 3-1 Ostapenko
Camille Pin
Former tour player on BBC Radio 5 live
Because Ostapenko was down, a set and 3-0, she has nothing to lose. She can just hit the ball. It makes a difference.
*Halep 6-4 3-1 Ostapenko
Boris Becker is looking resplendent in the Parisian sunshine. Smart open-necked shirt, fancy broad-brimmed straw sun hat. Looks like he is heading for a 'Man From Del Monte' audition after this. I'd buy a carton of OJ from him.
That 15-minute prediction is looking fanciful now (I was being a little contrary..). Especially as Ostapenko is not giving her serve up easily. Well, apart from when she chucks a couple of double faults in Halep's direction.
Ostapenko, the Chatrier crowd roaring on their encouragement, battles back in deuce though, clinching a nervy hold with a forehand winner.
Image source, AFPHalep 6-4 3-0 Ostapenko*
BBC tennis correspondent Russell Fuller has his say from Roland Garros.
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Halep 6-4 3-0 Ostapenko*
Fifteen minutes? That's how long I'm giving this match. Although we thought that when Halep was a set and a break down against Elina Svitolina in their quarter-final...
Halep races 40-0 ahead and looks to be coasting towards the hold. But wait! Ostapenko has other ideas.
The Latvian gamely fights back to deuce, forcing Halep to win the game all over again before finally being able to grab her seat at the changeover.
*Halep 6-4 2-0 Ostapenko
Camille Pin
Former tour player on BBC Radio 5 live
Jelena has hit a lot of winners but unfortunately she's a little bit down now.
She played a great first set but now she's thinking 'I've lost it. Halep is too solid for me today'.
Image source, AFP*Halep 6-4 2-0 Ostapenko
This is the longest game of the match so far - and it is vitally important, one would think, that Ostapenko holds here.
The 20-year-old palms Halep off as the Romanian sees another break point disappear. But Halepo bags the third one.
Ostapenko produces two more rogue forehands and the break goes to Halep after a slog of a nine-minute game.
Halep 6-4 1-0 Ostapenko*
Uh oh. Ostapenko is muttering to herself. Not surprising though as she coughs up another break point to Halep.
But she regains focus quickly, backing herself again to whack a forehand winner down the line. Deuce...
An ace brings up advantage, but a stray forehand pegs the Latvian back. On we go...
Halep 6-4 1-0 Ostapenko*
A comfortable hold will kick Halep off nicely in this second set. She doesn't get it.
A backhand winner from Ostapenko brings up three more break points but Halep battles back again to see them off.
That's four break points wasted by Ostapenko in this match now. You've got to take your chances...
Image source, AFPHalep 6-4 Ostapenko
Piers Newbery
BBC Sport at Roland Garros
As well as her coach, Darren Cahill, and family watching from courtside, Halep has a legend of Romanian tennis with her in Virginia Ruzici.
The 62-year-old former world number eight talent-spotted the young Halep and has managed her ever since. She is also the only Romanian woman to have won a Grand Slam title, on this court in 1978. All of which makes this a pretty emotional day for her, you would think.
Who needs friends on tour when you're winning tennis matches, eh?!
Jelena Ostapenko's got a reputation as a bit of a feisty young tyke. You may remember her clash with Britain's Naomi Broady last year at the Auckland Classic.
Broady fought her way back from 1-5 in the final set to beat Ostapenko and there was a bit of aggro between the pair.
Ostapenko threw her racket in anger at one point and it hit one of the young ball-boys. The boy was close to tears afterwards but the umpire didn't disqualify her, and instead it was Broady who found herself in tears as she argued with the official.
Apparently Ostapenko muttered that Broady's behaviour was terrible, and the Briton was critical of her opponent after the match. Even Andy Murray weighed in on the war of words, saying Broady was right to "stick up for herself".
Oooh errr.
Image source, Getty ImagesHalep 6-4 Ostapenko
And here's another stat that you Ostapenko fans won't like.
No woman has won the Coupe Suzanne Lenglen after losing the first set since Jennifer Capriati in 2001.
Halep 6-4 Ostapenko
She's done it! Simona Halep snaffles that third break - and the set.
Unforced errors again prove to be Ostapenko's downfall, three more helping the Romanian to draw first blood.
Here's that set in a statistical nutshell: Ostapenko made 23 unforced errors, Halep won just one winner...
Image source, Getty Images