World number one Simona Halep will have a third shot at glory in a French Open final after beating Garbine Muguruza — she will face American Sloane Stephens in the final.

Halep, a three-time beaten Grand Slam finalist including in 2014 and 2017 at Roland Garros, emphatically ended the impressive run of 2016 champion Garbine Muguruza with a 6-1, 6-4 victory on Thursday.

Halep's victory assured herself of retaining the No. 1 ranking, but it's that first Grand Slam title that still eludes the Romanian.

"I will try my best," Halep told the crowd at Court Phillipe Chatrier, "and hopefully I will be better than last year."

Her reward is a showdown with American Stephens, who maintained her perfect record against compatriot and friend Madison Keys, as she blazed into the final with a 6-4 6-4 win in a repeat of last year's US Open final.

In the first all-American Roland Garros semi-final since 2002, the 10th-seeded Stephens stayed composed throughout as Keys, who has not won a set against her in three meetings, peppered the court with unforced errors.

The 25-year-old Stephens will become the first American other than the Williams sisters to break into the top five in the WTA rankings since Lindsay Davenport — Keys's coach — in 2006. She will also become the first American finalist at Roland Garros outside of the Williams sisters since Jennifer Capriati in 2001.

"It's always hard to play someone from your country and such a good friend, but I'm happy I played my tennis," Stephens said.

"This is one of my favourite tournaments and I'm looking forward to Saturday. Merci Paris, je t'aime.

"I love playing here. So like I said, making the quarter-finals here was a big deal for me. I was really pleased. And obviously making the semis and finals, there is not much more you can ask for in a player."

mds (AP, Reuters)