Defending champion Roger Federer survived a major scare at the Australian Open yesterday, beating Gilles Simon 6-2, 6-3, 4-6, 4-6, 6-3 in the second round in Melbourne.

Novak Djokovic also won. Top-seeded woman Caroline Wozniacki, last year's finalist Justine Henin and 2008 champion Maria Sharapova also advanced.

No. 9 Li Na of China defeated Evgeniya Rodina of Russia 6-3, 6-2.

For a while, it seemed as if Simon, who had beaten Federer in their only two previous meetings, would send the Swiss star packing out of a Grand Slam before the third round for the first time since the French Open in 2003 - a total of 31 majors.

But Federer, pumping his fist increasingly in celebration with each point in the final few games, broke Simon's service in the sixth game of the deciding set to go up 4-2, held his service to go up 5-2, then held his serve two games later to clinch it on his fifth match point with an ace.

"I wasn't playing poorly in the third and fourth set, but Gilles took it to me," Federer said. "Clearly, he's a great player first of all. Matches against him don't come easily... hopefully we don't play each other anymore."

Earlier, Venus Williams fought through an injury to defeat Czech Sandra Zahlavova 6-7 (6), 6-0, 6-4.

"It was really tough, but I'm a long way from home and it's such a long way I didn't want to go back yet," Williams said.

"You've got to be able to play under all kinds of circumstances - good, bad, strange, weird, all of the above. I had to just calm myself down."

Her fighting spirit - and the strapping and perhaps a painkiller - helped continue a streak in which Williams has completed all 257 singles matches she has started at Grand Slams.

No. 3 Djokovic beat Ivan Dodig 7-5, 6-7 (10), 6-0, 6-2. Djokovic appeared comfortable all over the court against Croatia's Dodig, who nevertheless challenged Djokovic in the first two sets with a powerful serve and strong baseline shots. Djokovic answered with his own baseline winners.

Djokovic will next play his Davis Cup teammate Viktor Troicki after the 29th-seeded player beat Frenchman Nicolas Mahut 6-4, 6-2, 1-6, 6-3.

Wozniacki advanced with a 6-1, 6-0 win over American Vania King in the Danish player's first major as No. 1. The 20-year-old reached the third round for a 13th consecutive Grand Slam.

To get to the semis, Wozniacki might have to beat seven-time Grand Slam winner Henin, who continued her comeback from injury with a 6-1, 6-3 win over Elena Baltacha of Britain.

The pair could meet in the quarterfinals. Henin will have to get through a tough match against two-time major winner Svetlana Kuznetsova just to get past the third round. The 23-seeded Kuznetsova beat Dutch qualifier Arantxa Rus 6-1, 6-4.

"I have a lot of good memories, almost all good memories, from Melbourne," said Henin, the 2004 Australian champion and runner-up here in 2006 and last year, when she was returning from a career break from the tour.

No. 8 Victoria Azarenka beat Andrea Hlavackova 6-4, 6-4.

In other matches, Barbora Zahlavova Strycova of the Czech Republic beat Australian wild card Jelena Dokic 7-6 (3), 6-1.

On the men's side, Wimbledon finalist Tomas Berdych needed four match points to beat Philipp Kohlschreiber 4-6, 6-2, 6-3, 6-4.

Mardy Fish of the US made a second-round exit, the No. 16 seed losing 1-6, 6-3, 6-3, 6-3 to Spain's Tommy Robredo. And ninth-seeded Fernando Verdasco of Spain rallied from two sets down to beat Serbia's Janko Tipsarevic 2-6, 4-6, 6-4, 7-6 (0), 6-0, conceding just one service point in the last set.