Top-ranked Amelie Mauresmo will not finish the tennis season as the No. 1 player in the world.
Martina Hingis' 6-4, 3-6, 6-3 win over Nadia Petrova at the WTA Championships on Wednesday meant Justine Henin-Hardenne could not finish last in the Yellow Group, meaning the race for No. 1 was reduced to a two-woman battle.
Henin-Hardenne sits atop the group with a single win, while Hingis and Petrova share a win and a loss, and Mauresmo sits on the bottom with a defeat.
Mauresmo needed to defend her title, have Henin-Hardenne finish last in the group, and see No. 2 Maria Sharapova fail to advance past the semi-finals to retain the top ranking.
Sharapova will finish No. 1 if she wins the championships and Henin-Hardenne loses in the semi-finals or earlier. The Belgian will clinch her second year-end No. 1 if she reaches the final.
Sharapova is poised to advance to the semi-finals after beating Kim Clijsters 6-4, 6-4 to stay top of the Red Group.
In the other Red Group match, Svetlana Kuznetsova handed Elena Dementieva her second defeat with a 7-5, 6-3 win in an all-Russian match.
Sharapova has two wins to Kuznetsova's one, Clijsters has a single loss, and Dementieva two defeats.
Kuznetsova can guarantee her and Sharapova a place in the semi-finals should she beat Clijsters today.
"I think the quality of my tennis today was quite high," Sharapova said of her 10th straight win. "I know that I've played a lot of matches and I feel good."
US Open champion Sharapova kept Clijsters deep behind her baseline and on the run throughout, hitting crosscourt winners off both wings.
Sharapova held her break in the fifth game to take the first set.
After the 19-year-old Russian saved three break points in the fourth game of the second set, she took away the momentum from Clijsters, and broke the frustrated Belgium in the next game, which was mired in challenges that went against Clijsters.