MELBOURNE, Australia (AP) — Defending champion Roger Federer admitted he was lucky to survive 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.

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.

Simon is one of only three players on the ATP Tour to hold a winning record against the Swiss star, although Federer cut the margin. Simon’s series lead is now 2-1.

Federer’s win came on a day when one of the other stars of the tournament — fourth-seeded Venus Williams — nearly had to withdraw with a hip injury after the first set of her match, but recovered to advance to the third round.

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 again held his serve two games later to clinch it on his fifth match point with an ace.

Williams also had some drama getting through to the third round, overcoming a painful injury to beat Sandra Zahlavoa of the Czech Republic, 6-7 (6), 6-0, 6-4.

Novak Djokovic, Andy Roddick, top-seeded woman Caroline Wozniacki, last year’s finalist Justine Henin and 2008 champion Maria Sharapova also advanced.

Williams seemed to have the narrowest escape. Writhing in pain and clutching near her stomach as she walked back to her courtside chair, a WTA trainer was called and Williams took a medical timeout after the first-set tiebreaker.

She appeared to be on the verge of retiring, and certainly was on the verge of tears. But a few minutes later, she returned with her upper right thigh taped and later said she injured her “psoas” muscle, which flexes the hip and spinal column. That maintained her record of never retiring in a major tournament.

No 3 Djokovic beat Ivan Dodig, 7-5, 6-7 (10), 6-0, 6-2. Djokovic, who beat Jo-Wilfried Tsonga in the 2008 final in Melbourne Park for his only Grand Slam title, is in career-best form.

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.

No 8 Victoria Azarenka, the 2010 quarter-finalist who lost to Serena Williams each of the past three years, beat Andrea Hlavackova, 6-4, 6-4. Serena Williams is injured and not defending her title in Australia.