Clijsters, 26, posted a 6-4, 6-3 victory over France's Marion Bartoli in the first round. It was the first WTA Tour match for Clijsters, a former world No.1 player, since the spring of 2007.
She gave birth to a daughter since she retired to start a family and become injury-free.
Clijsters, who earned her lone major title at the 2005 U.S. Open, owns 34 singles titles and was ranked No. 1 for a total of 19 weeks in her prime.
Ninth-seeded Belarusian Victoria Azarenka beat Estonian Kaia Kanepi 6-3, 7-6 (7-2) and No. 11 Ana Ivanovic of Serbia beat American Melanie Oudin 2-6, 6-1, 6-1 Monday.
German Anna-Lena Groenefeld beat Frenchwoman Virginie Razzano 6-3, 3-6, 6-4 and Canadian Aleksandra Wozniak beat Spaniard Carla Suarez Navarro 6-0, 6-3.
Copyright 2009 by United Press International.