|Federer and Simon leave the court after the Frenchman almost derailed the Swiss master's title plans [Reuters]
Roger Federer survived a major scare in beating Gilles Simon in the Australian Open second round as Novak Djokovic and Andy Roddick also survived tough tests to join him in the third round.
Federer, the second seed, was two sets up before the Frenchman came back to win the next two on a day when there were also wins for Caroline Wozniacki and Justine Henin in the women's draw.
The Swiss then held his nerve to win 6-2 6-3 4-6 4-6 6-3, on his sixth match point, in a performance worthy of a final.
The result was tough on Simon, who was once as high as sixth in the world before injury plagued his last two seasons.
But he will take comfort in the knowledge that his form suggests he can again become a top-10 player.
Third seed Djokovic, champion in Melbourne three years ago, dropped the second set to lowly-ranked Ivan Dodig before pulling away from the Croat to win in four sets on Wednesday.
The Serbian will be pleased to come through the encounter, especially after the impressive performance of the 26-year-old Dodig.
The first two sets were tight affairs, which were eventually shared, before the higher-ranked Djokovic turned on the style to outclass his opponent 7-5 6-7 6-0 6-2.
He goes on to face Viktor Troicki in what promises to be a tough encounter between fellow countrymen who won the Davis Cup together at the end of last year.
American Andy Roddick, a four-time semi-finalist at Melbourne Park, had a slightly easier match to beat Igor Kunitsyn 7-6 6-2 6-3.
After a first set tie-break, the big serving eighth seed cruised through to an encounter with Robin Haase, who knocked out 26th seed Juan Monaco.
Both Mardy Fish (15th seed) and Albert Montanes (25th seed) were beaten by lower-ranked opposition, but Gael Monfils, Tomas Berdych and ninth seed Fernando Verdasco eased through.
World number one Wozniacki put her recent struggles behind her as she demolished Vania King 6-1 6-0.
The winners flowed off the Dane's racket, and the 20-year-old will be delighted at her improved form as she takes on Dominika Cibulkova, her conqueror in Sydney and 29th seed, in round three.
Former world number one Henin produced an impressive performance to oust British number one Elena Baltacha.
In a potentially tricky encounter, the Belgian star didn't allow her 55th ranked opponent many chances, brushing her aside 6-1 6-3.
Runner-up in 2010, Henin is likely to face a sterner test against two-time Grand Slam champion Svetlana Kuznetsova in the third round.
The former top-five player has seen her form dip in recent seasons, but could still pose a serious threat to Henin's title challenge.
Fourth seed Venus Williams survived an injury scare to limp through to the third round, but 15th seed Marion Bartoli, who impressed in round one, was dismissed in three sets.
Yanina Wickmayer and Kaia Kanepi were further seeded casualties, but Victoria Azarenka and Sydney winner Li Na progressed.