Novak Djokovic won his opening match at the China Open by defeating German qualifier Michael Berrer 6-1, 6-7 (3), 6-2 on Tuesday in his first match since losing the U.S. Open final.

The Serb is a two-time winner in Beijing and remained undefeated at the tournament after converting both his break points in the third set, and holding his own serve throughout the match.

Third-seeded Jo-Wilfried Tsonga also advanced by beating Uzbekistan's Denis Istomin 4-6, 6-1, 7-6 (3) with the help of 14 aces, while Russia's Mikhail Youzhny beat seventh-seeded Tommy Haas of Germany 6-4, 4-6, 6-2.

In other first-round matches, Nikolay Davydenko defeated qualifier Alex Bogomolov Jr. 7-5, 6-1 in an all-Russian matchup, Jurgen Melzer of Austria hit 12 aces to beat Pablo Andujar of Spain 6-1, 4-6, 7-6 (3), and Andreas Seppi of Italy advanced when Julien Benneteau of France had to retire with an injury to his right arm while trailing 6-1, 2-0.

In the second round of the women's tournament, top-ranked Victoria Azarenka and No. 3 Agnieszka Radwanska both advanced with straight-set victories.

Azarenka beat Sabine Lisicki of Germany 6-4, 6-2 while Radwanska ousted Chinese wild-card entry Zhang Shuai 6-2, 6-3.

Chinese home favourite Li Na easily dispatched Nadia Petrova of Russia 6-1, 6-2, and the former French Open champion said she has improved under new coach Carlos Rodriguez.

"He's not only teaching me how to play better tennis, he's teaching me how to be on the court," Li said. "Before I would explode easily on the court; I think I've changed a lot since we've started working together."

In other women's matches, fifth-seeded Angelique Kerber, No. 10 Caroline Wozniacki and former top-ranked Jelena Jankovic all advanced.