Tennis:Serena Williams advanced to the fourth round of the Australian Open after coming back from the brink of defeat to down fifth seed Nadia Petrova 1-6 7-5 6-3 today.
A winner in Melbourne in 2003 and 2005, Williams is unseeded after her ranking slipped substantially in 2006, when she missed much of the year with a left knee injury.
The 25-year-old American enjoyed straight set wins against 27th seed Mara Santangelo in the first round and Anne Kremer of Luxembourg in the second but was in trouble against Petrova early on as the Russian claimed the opening set 6-1 in 29 minutes.
Williams won the first three games of the second set but promptly dropped five in a row to allow Petrova to serve for the match.
However, the American held serve to end the streak before breaking Petrova twice to level the match at a set apiece.
"I really had no other option than for my game to go up," Williams said.
"I was down 3-5 and on the verge of being out of the tournament, and I obviously didn't want that to happen. ... I told myself just to stay in there and do what I had been practising and it'll come together sooner or later."
Petrova said: "Serena raised her game a little bit, and I started to be a little bit more careful on the court."
In a back-and-forth third set, Williams claimed the first two games and Petrova the next two, before the American broke Petrova in the sixth game and held for a 5-2 advantage.
She then closed out the Russian two games later for victory.
"I think it was a good test of my fitness," Williams said. "I'm fit and I'm ready. I felt like I had another game to play after the match."
Williams will face either 11th seed Jelena Jankovic of Serbia, who beat Victoria Azarenka of Belarus 6-3 6-4.
Second seed and defending champion Amelie Mauresmo and third seed Svetlana Kuznetsova are also through to the fourth round.
Mauresmo took just over an hour to dispose of Eva Birnerova of the Czech Republic 6-3 6-1, while Kuznetsova defeated 26th seed and fellow Russian Maria Kirilenko 6-1 6-4.
Mauresmo's fourth-round opponent will be unseeded Lucie Safarova of the Czech Republic, who went through when her Belorussian opponent Anastasiya Yakimova retired after losing the first set of their match 6-3.