Justine Henin-Hardenne clinched the year-end number one spot and a place in the final of the WTA Championships when she ended Maria Sharapova's 19-match winning streak with a 6-2, 7-6 victory over the Russian on Saturday.
The Belgian will meet defending champion Amelie Mauresmo, who earned her place in Sunday's final with an enthralling 6-2, 3-6, 6-3 victory over Kim Clijsters.
Mauresmo beat Henin-Hardenne to win both the Australian Open and Wimbledon this year and enjoys a 6-5 advantage in head-to-heads after her victory in Friday's round-robin match.
Three-times French Open champion Henin-Hardenne, who reached the final of all four grand slams this year, produced a wonderful display full of guile and determination to overcome Sharapova and secure her place in a first Championships final.
The 19-year-old Russian, who had not dropped a set on the way to the semi-finals, looked bemused as the Belgian returned everything she could throw at her and was never able to get into her stride.
"I feel very happy with the way I coped with the pressure and with the aggressive way I played," Henin-Hardenne said.
"I loved the match and felt confident throughout and I thought she (Sharapova) was nervous. I took my chances.
"I'm number one now but my season is not over yet and I want to win these Championships."
Sharapova said she had been unable to match the heights of her performances in previous matches.
"I didn't feel like myself today," said the U.S. Open winner. "There are going to be days when you are not playing your best and you hope to find ways to break through, but when you come up against someone like Justine it is not easy."
Mauresmo, who went into the Championships as the top-ranked woman in the world, got the better of double winner Clijsters in a titanic struggle at the Madrid Arena.
The Frenchwoman won the first set convincingly but the battling Clijsters hit back to take the second.
There was nothing to separate the two players until Mauresmo got the crucial break in the deciding set to go 5-3 up after a failed line-call challenge from Clijsters and then served out for victory to give her a chance to defend her title.
ASTUTE SERVING
Henin-Hardenne, who returned to action this week following a two-month lay-off with a calf injury, took the game to Sharapova from the off, forcing her opponent into a series of uncharacteristic errors with her pin-point backhand and astute serving.
She won the opening game with a cleverly disguised drop shot and then broke serve after working her opponent around the court with some perfectly placed ground strokes.
The Belgian manufactured three break points in the sixth with a wonderful passing shot down the line and went 5-1 up when Sharapova double faulted.
Sharapova broke back in the seventh but Henin-Hardenne stayed focused and broke again to take the set after a volley error.
The Russian tried to battle her way back into the match with her trademark lashing forehands but Henin-Hardenne made her work for every point and held her serve with authority.
It was level pegging until the Belgian turned the screw in the eighth game of the second set to earn herself five break points and go 5-3 up.
Sharapova refused to give up without a fight however and broke back when her opponent was serving for the match but Henin-Hardenne kept her nerve to win the tie-break 7-5 and gain some measure of revenge for her defeat in the final of the U.S. Open.
