Zheng Jie?meets the media after beating Barbora Zahlavova Strycova of Czech Republic 6-0, 6-4 to finish off her second-round match at the Australian Open in Melbourne on Thursday. [Photo/Xinhua]

MELBOURNE - Serena Williams beat Barbora Zahlavova Strycova of Czech Republic 6-0, 6-4 to finish off her second-round match at the Australian Open here on Thursday and her 500th career win, while Chinese Zheng Jie advanced to the next round of both women's singles and double event in four hours.

With today's win, 12th-seeded Williams extended her winning streak to 16 matches at Melbourne Park, where she won back-to-back titles in 2009 and 2010 but missed last year's event because of injury.

Williams now has 104 losses and 500 wins, which is something she'd wanted to achieve since her older sister Venus passed the milestone. Venus Williams, a seven-time Grand Slam winner with a career win-loss record of 598-147 as a pro, is skipping the Australian Open to recover from illness.

"I knew I had to get there, too, because I do everything she does," ?Serena Williams said.

China's Zheng Jie first faced an easy draw against Roberta Vinci in the second round, beating the Italian 6-4, 6-2, and then paired with Slovenian Polona Hercog, to defeat France pair Mathilde Johansson and Pauline Parmentier 6-2, 6-2 in the opener of the women's doubles.

Zheng remained unbeaten this season after winning the season opener, ASB Classic tournament contested in Auckland earlier this month.

"Remaining unbeaten is also a great thing for me," said Zheng, who wasted nearly the whole season in 2011 because of her wrist injury, "It will give me much more confidence to go forward, especially in the Australian Open, the first Grand Slam this year." Both players could not hold their serves in the first set. When they tied at 4:4, Zheng and Vinci both held only one serve only, but the Chinese then turned the table upon her opponent. She clinched the next two games to take the set with 6-4.

Zheng dominated the second set, broke serve in the fifth game and held her serve to take the lead at 5-2. Trailing with 40-15 in the eighth game, Vinci launched a strong comeback to save seven match points, but a strong forehand return was enough for the Chinese to move into the third round with a resounding straight sets triumph.

Peng Shuai, who's going to pair Zheng in June's London Olympics for women's doubles, failed to reach the second round today after partner Francesca Schiavone of Italy, who won women's singles title in 2010 French Open, retired because of shoulder injury.

Peng will pair British Jamie Murray, 4ht-seeded Andy Murray's elder brother, to compete in Friday's mixed doubles first round.

Big names are untroubled. Defending champion Novak Djokovic blasted Colombia's Santiago Graldo with straight sets to advance into the second round of men's singles while 2008 Australian Open women's singles winner Maria Sharapova beat qualifier Jamie Hampton of the United States 6-0, 6-1 to seize a second round victory in 64 minutes.

Andy Murray, David Ferrer, Jo-Wilfried Tsonga and Janko Tipsarevic all advanced into the top 32 while 15th-seeded American Andy Roddick's retirement handed host qualifier and former world's No.1 Lleyton Hewitt a easy second-round win.

Rafael Nadal and Roger Federer will headline Friday's day session on Rod Laver Arena, with host-favourite Bernard Tomis facing No.13 seed Alexandr Dolgopolov, followed by Li Na against Anabel Medina Garrigues.