MADRID (AFP) -- World number three Justine Henin-Hardenne of Belgium ensured herself a berth in the semifinals of the WTA Tour Championships here on Thursday with a 6-4, 6-4 win over Russia's Nadia Petrova.

The diminutive Belgian took exactly 100 minutes to see off her fifth-ranked opponent and ensure her progress with a match against world number one Amelie Mauresmo still to come.

Mauresmo got her challenge back on track by beating Switzerland's Martina Hingis 3-6 6-1 6-4.

After losing her opening match to Petrova 6-2 6-2 the Frenchwoman now needs to beat Henin-Hardenne to qualify for the semifinal.

"It's a great feeling to qualify for the semis," said French Open champion Henin-Hardenne. "I missed the last two editions of the championships with injury and now I'm coming back from a few weeks off so it's great to be back on top."

If Henin-Hardenne can win her semi then she will end the season as world number one.

But the Belgian insists that grabbing the top spot in the world, which she first occupied in 2003, would not alter her campaign here.