The world No. 1, who has lifted the Australian Open and Wimbledon titles in her best season ever, took just 69 minutes to reach the quarterfinals at the Beijing tennis centre after a bye.

"I'm happy about the game I played," said Mauresmo. "It was not easy to wait so long to play. I'm happy I finally got my first match here. I'm looking forward now to the next round."

Serbian sixth seed Jelena Jankovic beat out another French woman, Marion Bartoli, 6-3, 6-2.

"I played really well today, concentrated and tried to play the best I can," said Jankovic, who lost 10 of her first 11 matches this season before turning the corner at Rome in May with a quarterfinal and a change in attitude.

"I wasn't enjoying the game at all, and I wasn't fighting. I was not the same person as I am now. I wasn't concentrating at that time," said the No. 17 Serb.

Russian third seed Nadia Petrova moved into a quarterfinal matchup with Jankovic as she crushed Greek Eleni Daniilidou 6-1, 6-2 in 67 minutes, firing ten aces while saving all eight break points she faced.

American Lindsay Davenport and Russian Elena Vesnina were both facing second-round matches against Chinese opponents.

Mauresmo earned the first set against Sun, the 2004 Athens Olympic doubles gold medallist, in 36 minutes, recovering after losing an early break of serve.

But the top seed wasted no time in consolidating, collecting a break to start the second set and reaching a 5-1 lead against the No. 111 from Beijing.

Sun saved one match point before Mauremso advanced with four breaks of serve and five aces in her efficient debut at the event.

Mauresmo won her 44th match of the season against just 10 defeats, in a 2006 campaign which has so far netted four titles.