Former champion Marat Safin survived another tense five-set match to beat 21-year-old Israeli Dudi Sela 6-3, 5-7, 4-6, 7-6, 6-0 in the Australian Open second round on Wednesday.

Travelling down distinctly different road, Safin is headed for an explosive third-round collision with Andy Roddick.

The American sixth seed came out firing against Frenchman Marc Gicquel and accelerated to a 6-3, 7-6, 6-4 win.

Safin, champion in 2005, again chose a more winding route.

"We're both better than a third round match-up against each other but that's the way it shakes out," said Roddick. "We both have to deal with it. I'm sure he's not thrilled about it either."

In the women's draw, former champions Amelie Mauresmo and Serena Williams motored into the third round of the Grand Slam.

Mauresmo took another confident step in the defence of her Australian Open crown when she swept aside Russian teenager Olga Poutchkova 6-2, 6-2 while Williams beat Luxembourg's Anne Kremer 7-6, 6-2.

Safin, who missed last year's tournament through injury, was within two points of defeat in the fourth set before coming through his second marathon contest in three days.

Safin, seeded 26th, started well and overpowered Sela in the first set, but the Israeli, ranked 202nd in the world, grew in confidence as his opponent started to make errors and took the next two.

Safin broke Sela's serve twice in the fourth set but the 21-year-old Israeli hit back to level and was two points from victory when the players were forced off court by rain.

The delay galvanised Safin, however, and he held serve to set up a tiebreak he won 7-4 before romping through the final set to clinch victory in three hours 21 minutes.

The Russian has now won 26 of 37 five-set matches in his career but cannot afford such lapses against a man who owns the fastest serve in the game.

Mauresmo looked below her best and was a break down at 2-1 in the second, but recovered to book her place in round three after 72 minutes on Rod Laver Arena.

The second seed broke three times in the first set against the 19-year-old, clinching the opener in 37 minutes before Poutchkova threatened a comeback with her early break in the second.

The Wimbledon champion broke back immediately, reeling off five games in a row to progress to round three where she will face the Czech Republic's world number 83 Eva Birnerova.

Earlier, Williams slapped a backhand winner to set up a third round showdown with Russian fifth seed Nadia Petrova.

"I feel excited to go into the match. I'm ready to go," declared Serena, who holds a 5-1 record against Petrova.

Unseeded at these championships after her ranking nosedived following an injury-plagued 2006, Williams was left grimacing and yelping in the first set as she dropped her serve to hand Kremer the initiative.

But the American got her act back together and after winning the tiebreak, thundered to a 4-0 lead before sealing the win in 95 minutes.

"I lost a little focus when I was 4-0 up. I started daydreaming," said the American, who has failed to win a title of any kind since lifting her seventh grand slam trophy in Melbourne Park in 2005.

"I'm too experienced to daydream at that stage of the match."