Kim Clijsters celebrated taking over the No. 1 ranking by reaching the Open Gaz de France final with a 6-1, 7-5 win over third-seeded Kaia Kanepi of Estonia.
The top-seeded Belgian, who will replace Caroline Wozniacki as No. 1 on Monday, will play Petra Kvitova of the Czech Republic in Sunday's final as she aims for her 42nd title.
''I played aggressive, went for the line and tried to make her move,'' Clijsters said.
The fourth-seeded Kvitova thrashed American Bethanie Mattek-Sands 6-2, 6-0.
Clijsters has won both her previous meetings with Kvitova in straight sets. The second of those wins came on her way to winning the U.S. Open title for the third time in September.
''(Kvitova) always likes to play forward, she has this easy hit, very deep as well. Over the last few months she's been able to stay a little more consistent,'' Clijsters said. ''When I played her at the U.S. Open, she was really on (form) three games in a row ... (opening) up the court with that slice out wide with the serve.
''But then she could also make so many unforced errors and rush into it.''
Kvitova broke Mattek-Sands' serve three times in each set and wrapped up her victory in just 59 minutes with a powerful serve that Mattek-Sands could only get the tip of her racket to.
''I played my best match of the week. I was focused on every point,'' Kvitova said. ''I was in the final in Brisbane, but this is a bigger final and I'm looking forward to it.''
The 20-year-old Kvitova was a quarterfinalist at last month's Australian Open. Her title this year came at Brisbane, Australia.
''I don't think I will be stressed, because she is the best player (and I have) nothing to lose,'' Kvitova said.
The 27-year-old Clijsters raced into a 4-0 lead before Kanepi finally won a game.
''She made a lot more unforced errors, really wasn't playing as aggressive as I thought she would,'' Clijsters said. ''She was not making her first serves quite as much, that gave me more advantages at the start of the rally.''
Clijsters was not always at her best, and dropped her serve three times in a scrappy second set where she trailed 4-2 and 5-4 with Kanepi even serving to level the match.
''I didn't serve quite as well, and she started going for it a bit more, tried to keep the rallies a bit shorter,'' Clijsters said.
Clijsters set up her first match point by winning a long rally. She retrieved Kanepi's excellent drop shot and whipped a backhand crosscourt winner.
After saving the first two match points, Kanepi then hit a backhand return into the net. Kanepi lost her serve seven times in a match lasting 1 hour, 20 minutes.
Earlier, Mattek-Sands, who was unseeded, struggled throughout, winning only 30 percent of points on her second serve, allowing Kvitova to pick her off easily.
