MONTREAL (AFP) Reigning US Open champion Kim Clijsters and 2009 US Open runner-up Caroline Wozniacki, the world number two, advanced to the third round of the two million-dollar WTA Montreal Cup on Wednesday. Belgian fifth seed Clijsters outlasted 101st-ranked US qualifier Bethanie Mattek-Sands 4-6, 6-4, 6-3 to book a round-of-16 meeting with Estonias Kaia Kanepi, who ousted Austrian Sybille Bammer 7-5, 6-2. Clijsters trailed 4-1 in the second set and fought off two more break points before battling back to force a third set, then surrendered a service break before breaking Mattek-Sands twice to advance. After winning her 38th career title last week in Cincinnati, Clijsters has shown the form that helped her win her second Grand Slam crown last year after barely returning from a two-year break to start a family. Wozniacki, who like all top-eight seeds received a first-round bye, defeated Swiss Patty Schnyder 7-5, 7-5, to remain the highest-ranked player still in qwuest of the Canadian crown. Top seed Jelena Jankovic of Serbia went out for the second week in a row at the hands of a qualifier while US third seed Venus Williams pulled out last week with an injury, joining her top-ranked sister Serena on the injured list. Wozniacki, who has won four of her five matches against 52nd-ranked Schnyder, won two weeks ago at her hometown of Copenhagen and passed Jankovic to become world number two on Monday. The Dane will next face Italys Flavia Pennetta, who eliminated Russian Alisa Kleybanova 6-3, 6-3. Italian sixth seed Francesca Schiavone outlasted Russian Ekaterina Makarova 6-4, 6-7 (5/7), 6-2 to book a third-round date against Russian Dinara Safina, the 2008 Montreal winner who ousted compatriot Nadia Petrova 7-5, 4-6, 6-4. Also advancing was Polish seventh seed Agnieszka Radwanska, who ousted American Vania King 6-0, 6-3. Japans Kimiko Date Krumm withdrew due to a left quadriceps strain, handing Frances Marion Bartoli a walkover into a match against Czech qualifier Iveta Benesova, who ousted Jankovic on Tuesday. Victoria Azarenka of Belarus beat Russian Maria Kirilenko 6-4, 6-1 to book a third-round match with Chinas Li Na, a ninth seed who took a bye after Williams pulled out and is now the highest seed in her quarter of the draw.