BEIJING — Reigning China Open champion Victoria Azarenka crashed out in the first round Monday as the second seed faced stiff resistance from former finalist Andrea Petkovic. The Belarusian world No. 2 rarely showed glimpses of the form which helped her claim the title last year, at times appearing sluggish as she committed a staggering 15 double faults in the 6-4, 2-6, 6-4 loss. It is the second early exit in a row for the 24-year-old, who complained of feeling ill when she was defeated by Venus Williams in the second round of the Pan Pacific Open last week. Azarenka appeared agitated in the opening set in Beijing's National Tennis Centre, even before German Petkovic broke her serve following a string of double faults. The second seed regained her composure in the second set and appeared to be on course for victory when she broke Petkovic at the start of the third set. However, the 2011 finalist then seized the initiative, claiming victory in two hours and 22 minutes. China's Zhang Shuai continued her sizzling form, defeating compatriot Peng Shuai 6-3, 6-3 to set up a second-round match against tenth seed Roberta Vinci. Wildcard Zhang won her first WTA title in Guangzhou earlier this month. The 24-year-old recruited her own coach in July, following Chinese star Li Na's example in leaving the tightly controlled state sports system, raising hopes that she can emulate the success of the 2011 French Open winner. It was a successful day for three Serbian players. Eighth seed Jelana Jankovic needed three sets to overcome Russian Anastasia Pavlyuchenkova 1-6, 6-4, 6-0. Compatriot Ana Ivanovic claimed victory over Italian Flavia Pennetta 7-6 (11-9), 6-1. Bojana Jovanovski rounded off a hat trick for the Serbians, beating Romanian Sorana Cirstea 6-3, 6-2. Also in the first round, Canadian Eugenie Bouchard defeated Slovakia's Magdalena Rybarikova 6-4, 6-1 and Russia's Svetlana Kuznetsova swept aside Hsieh Su-wei of Taiwan 6-1, 6-1. The men's tournament got under way Monday, but it was heartbreak for the home crowd after China's top-ranked player fell at the first hurdle. Zhang Ze was knocked out by Australian No. 1 Bernard Tomic 7-6 (7-4), 6-4. Tomic will now take on fifth seed Richard Gasquet. Australian Lleyton Hewitt knocked out seventh-seeded Tommy Haas of Germany 7-6 (6), 6-3 in the first round. In the doubles, wildcard entrants Serena and Venus Williams wasted chances to win before losing 6-7 (3), 6-4, 11-9 to Liezel Huber and Taiwan's Chan Hao-ching. Tsonga beats Monfils In Tokyo, second-seeded Jo-Wilfried Tsonga needed four match points to beat Gael Monfils 6-3, 7-6 (8) Monday to advance to the second round of the Japan Open. Tsonga fired 11 aces and didn't drop a service game in the match to improve his record to four wins in five tour-level matches against his French compatriot. After Tsonga got the decisive break of the first set in the second game, the second set went with serve until the tiebreaker. Monfils rallied from a 5-1 deficit to level the tiebreaker at 5-5, then fought off three match points before Tsonga sealed the victory. “I started well and played offensively,” Tsonga said. “I know this is the only way for me to beat Gael.” In other first-round action, sixth-seeded Nicolas Almagro of Spain beat German qualifier Benjamin Becker 7-6 (4), 7-6 (3) and Alexandr Dolgopolov of Ukraine defeated Daniel Brands of Germany 6-3, 6-1. Top-seeded Juan Martin del Potro of Argentina was scheduled to play Marcos Baghdatis of Cyprus in a first-round match Tuesday, when defending champion Kei Nishikori was due to meet Jurgen Melzer of Austria. — Agencies