By Vienna Ma
MELBOURNE, Jan. 20 (Xinhua) -- David Nalbandian on Thursday retired from his Australian Open second round match, while Rafael Nadal, Andy Murray, Kim Clijsters and Vera Zvonareva all reached third round.
Argentina's Nalbandian retired when trailing 1-6, 0-6, 0-2 against Lithuania's Richard Berankison.
The 27th seeded Nalbandian edged out Lleyton Hewitt in his first match 3-6, 6-4, 3-6, 7-6(1), 9-7 in four hours and 48 minutes.
"Today I was like empty, you know?" Nalbansian told reporters in Melbourne on Thursday. "It is tough, very tough...I toss a ball for the serve and everything was moving around."
He called a doctor and was told dangerous playing like that.
Berankis will now play Spanish seventh seed David Ferrer in the third round on Saturday.
Meanwhile, China's Peng Shuai, ranked 54th in the world, shocked eighth seed and former world number one Jelena Jankovic 7-6(3), 6-3 as she equalled her best ever Grand Slam performance in the tournament's biggest upset so far.
"Maybe I believe more in myself now," Peng said. "I was really happy with today's win, I thought I played well."
"At first I was really nervous on centre court. She's a good player."
Peng's victory sustains China's good showing in the women's draw at the Australian Open after her compatriots Li Na and Zheng Jie both reached the semi-finals last year. Peng will next meet Japan's Ayumi Morita.
Top seed Rafael Nadal swept into the third round of the Australian Open with a straight sets win over American Ryan Sweeting 6-2, 6-1, 6-1 in the one hour and 42 minutes round two match.
Nadal now faces 18-year-old Australian Bernard Tomic on Saturday's third round.
British fifth seed Andy Murray cruised past Illya Marchenko of Ukraine 6-1, 6-3, 6-3 to progress. He will face Spanish Guillermo Garcia-Lopez.
Australian Open favorite Kim Clijsters remained in destructive form as she defeated Spain's Carla Suarez Navarro 6-1, 6-3 in just 62 minutes.
Clijsters described Suarez Navarro as a "tricky" player.
"She's a tough player - I've practiced with her before but I was happy with the way I played," Clijsters told reporters. She will meet Frenchwoman Alize Cornet in next match.
Second-seeded Vera Zvonareva overcame a shaky start to beat Bojana Jovanovski of Serbia 2-6, 6-3, 6-1 and set up a meeting with 35th seed Czech Lucie Safarova next.
Australian No.1 Stosur called on her powerful forehand to fight off a challenge from Russia's Vera Dushevina to move into the third round after winning in two sets, 6-3, 6-2. She will next play Czech Petra Kvitova.