Richard Gasquet knocked out former tennis classmate Jo-Wilfried Tsonga 1-6, 6-4, 6-2 to reach his fourth semi-final in six months at the Brisbane International on Friday.

Tsonga, last year's Australian Open finalist, will face off on Saturday against Czech Radek Stepanek, who defeated Swede Robin Soderling 2-6, 6-4, 6-3.

Tsonga, who attended a French tennis academy with Gasquet, won the opening set in less than half an hour but faded as his seventh-seeded compatriot took charge to earn the victory.

After the match Gasquet said he felt the pressure during the first set.

"I had pressure at the start of the match," said Gasquet. "I tried to concentrate on every second of my points. He's one of the best players in the world and is difficult to play against."

Tsonga was diplomatic in defeat. "Sometimes you play the best, sometimes you don't play the best, sometimes you make an incredible shot, sometimes you miss. This is tennis."

Amelie Mauresmo fell victim to a leg injury after less than half an hour on court to hand over a 4-0 victory which put French compatriot Marion Bartoli into the women's final.

The 2007 Wimbledon finalist will face off for the trophy against second seed Victoria Azarenka, who defeated Italy's Sara Errani 6-3, 6-1.

Mauresmo, a former Wimbledon and Australian Open champion, was fresh off an upset win the day before against top seed Ana Ivanovic.

But the French veteran had to call for the trainer after just 25 minutes on court against Bartoli before quitting the contest.

"It was something that I have had before - six months ago," she said. "This was the most reasonable and sensible decision to make sure that I'm am good for Melbourne (starting a week from Monday)."

Bartoli said she noticed that her opponent was favouring her leg in the third game of their abbreviated contest. "I saw she stopped her movement. I tried to keep my focus. But it's a heartbreaker, I knew it was quite bad."

"Still, I'm happy to be in the final."

Mauresmo got treatment on court to her left thigh and lower back. "I wanted to keep going, but I couldn't push off the serve.

"It's frustrating, you don't want to end it like this. But I want to be 100 per cent for Melbourne. I hope that nine days is enough time for it to get better."

Second seed Azarenka beat Bartoli in their only previous match at the Open two years ago. "I just want to do better than the last time and win my first title."