Samantha Stosur advanced to her first final of the year with an impressive three-set win over highly-rated young American Sloane Stephens at the Strasbourg International.

In a major morale-booster ahead of the French Open starting on Sunday, Stosur overcame gusting winds and a second-set surge from the American to see off Stephens 3-6 6-3 6-0 on Friday.

Her victory came hours after the former French Open runner-up was thrust into a likely third-round showdown at Roland Garros with defending champion Maria Sharapova.

Despite the challenging draw, Stosur will be full of confidence arriving at Roland Garros and gets the chance on Saturday to complete a dream build-up for the claycourt slam with a first WTA title since going back-to-back in Osaka last October.

“I’m really pleased. All week I’ve played well,” Stosur told AAP by telephone.

“It’s always good getting some tough matches and my timing’s been good, so I’m doing all the things you want to be doing heading into a grand slam.”

Stosur will meet another rising star in the final after Kristina Mladenovic’s unusual week took another twist when her semi-final opponent, French compatriot Virginie Razzano, retired with an abdominal injury.

Mladenovic, who received a walkover in the previous round when top seed Madison Keys withdrew with an elbow injury, was leading 6-3 1-2 against Razzano and had mixed emotions about reaching her maiden WTA final in such fashion.

“It’s definitely not the way I would like to go into the final, especially against a good friend of mine,” she said.

“But, still, I thought it was a great battle and I’m happy I managed to win the first set which was very high intensity.

“I’m very happy with how I’m playing this week.”