Coco Gauff battled past Madison Keys 6-7(6) 6-4 6-1 to reach the Roland Garros semi-finals.
It was a nervy and scrappy contest which saw neither player play their best tennis for the first two sets but Gauff stepped up when she needed to.
An error-prone match was produced with Keys hitting 60 of the 101 unforced errors in a rollercoaster contest.
Now Gauff will play either sixth seed Mirra Andreeva or French wildcard Lois Boisson in the last four.
It was a scrappy contest which was highlighted in the opening exchanges with the first three games going against the serve.
However, it was Keys who took control of the contest by breaking with some aggressive forehands to take a double break lead at 4-1.
Back came Gauff though as neither player consistently played their best tennis and the former finalist secured two consecutive breaks back for 4-4.
There was a lack of confidence from both sides under the Court Philippe-Chatrier roof with Keys having to save set point in the tenth game.
Having resorted to basics, Gauff ensured the first set would be decided by a tiebreak and initially took control of the tiebreak as the world number two took a 4-2 lead.
Once again there would be more turns in the match as Gauff played the better tennis when it mattered most and more big forehands secured the tiebreak 8-6 to take a one set lead.
In the second set it was Gauff who was the more aggressive on serve with unforced errors flying from Keys’ racket.
At times it was a painful watch from the Australian Open champion who was forced to save four break points in the opening game.
The impressive start from Gauff was rewarded though as she broke twice to take a 4-1 and double break lead.
Yet again there were more twists and turns as Gauff kept missing some easy shots with it being Keys’ turn to level up the deficit at 4-4.
Although her double break lead was gone, Gauff was determined not to make proceedings difficult in the second set and immediately broke back.
An edgy service hold was produced from Gauff as she levelled things up at one set all.
In the deciding set Keys played a stunning first point but had very little to show after it as the forehand was not working consistently enough.
It was Gauff who consistently played her best tennis of the contest in the deciding set to cruise past an erratic Keys, breaking three times to seal the win.
A huge roar from Gauff followed as she is into the semi-finals at Roland Garros and looks to reach her second final in Paris.
After the match Gauff said she just had to fight for every point, “Madison [Keys] was playing well so I was just trying to get the ball deep and be aggressive, but it’s tough because she was hitting the ball so fast and so low,” Gauff was quoted by the BBC Sport website as saying in her on-court interview.
“She is obviously a very great player and her forehand is probably one of the best, if not the best, on tour. I was just trying my best to get it on the other side of the court, but she has a great inside-out and inside-in forehand.
“I was just trying to fight for every point. Honestly I knew that I just had to be able to run today. As soon as the ball came short, I knew I had to punish her for it.”
Now Gauff will play Mirra Andreeva, who she has beaten in both Madrid and Rome this year, or Lois Boisson in the semi-finals on Thursday.
