French Open: Simona Halep stunned by Amanda Anisimova in the quarter-finals

American 17-year-old will face Australian eighth seed Ashleigh Barty, who defeated Madison Keys in Thursday's other last-eight tie

Tennis - French Open - Roland Garros, Paris, France - June 6, 2019. Amanda Anisimova of the U.S. celebrates after her quarterfinal match against Romania's Simona Halep. REUTERS/Charles Platiau

Defending champion Simona Halep was eliminated from the French Open quarter-finals as 17-year-old Amanda Anisimova continued her remarkable run at Roland Garros on Thursday.

Anisimova, the world No 51 from the United States, produced another dominant performance on the Paris clay to beat the Romanian third seed 6-2, 6-4.

Halep had been looking to become the first woman to retain her title at Roland Garros since Belgian Justine Henin won three times in a row from 2005-07.

The unseeded Anisimova, the first player born in the 2000s to reach the last eight at a grand slam, can become the first teenager to lift the trophy here since Iva Majoli of Croatia prevailed in 1997.

"This is honestly more than I could ever have asked for," said the teenager, who is yet to drop a set at Roland Garros. "That was one of the best matches I have ever played."

Anisimova faces another top player in the semi-finals after Australian eighth seed Ashleigh Barty defeated Madison Keys 6-3, 7-5 in Thursday's other quarter-final.

Both matches were originally scheduled for Wednesday only for rain to wash out the entire day's schedule.

Barty's greater variety proved too much for 2018 semi-finalist Keys, whose power game broke down at the vital moments.

A reflex backhand winner gave 23-year-old Barty the decisive break when Keys served at 3-4 in the first set.

Using her clever changes of pace, she provoked errors from the powerful Keys to break again at 3-3 in the second.

Serving for the match at 5-4, Barty wavered for the first time in the match, double-faulting and then netting a forehand on break point to hand Keys a way back into the match.

But the respite was shortlived. Keys dropped serve with a double-fault in the next game and this time Barty sealed victory to set up a semi-final clash with American teenager Amanda Anisimova who knocked out defending champion Simona Halep.

"Anisimova has been playing some great tennis, to reach a semi-final you must be doing the right things," Barty, who once quit tennis to play cricket, said on court.

"It's an exciting opportunity for both us and we will both enjoy it tomorrow."

There is now guaranteed to be a first-time grand slam winner at the French Open, with the other semi-final to be contested by British 26th seed Johanna Konta and 19-year-old Czech Marketa Vondrousova.

Konta had beaten last year's finalist Sloane Stephens to reach the last-four, while Vondrousova - who is yet to lose a set at the French Open - defeated Petra Martic. Both players have had extended rests having last played on Tuesday.