Against all the odds, and not least his own expectations, Greg Rusedski pulled off the victory of his life in the second round of the Australian Open, defeating Brazil's world number one Gustavo Kuerten over five pulsating sets during which the home crowd on the floodlit Rod Laver court took the battling Brit to their hearts.

And small wonder. For after an awkward opening set, when he twice dropped his serve, Rusedski hurtled around the baseline like a man demented, running down Kuerten's raking ground strokes, forcing the Brazilian to try for winners again and again, and then frequently launching himself to left and right at the net for a thrilling series of scintillating volleys. Rarely can he have played the shot better. The result was a remarkable 4-6, 6-4, 6-3, 2-6, 97 victory.

Rusedski's seemingly infinite capacity to surprise has always been one of his most endearing traits. Time and again he has bounced back from adversity and injury. Until last year, that is, when his season was virtually cut in half and he ended up losing more matches than he won, thereby dropping out of the world's top 50. There were fears his career might be almost over, but it was typical of the man that he refused to consider the thought.

Instead, under the guidance of Australia's Pat Cash, the former Wimbledon champion whose own career was heavily injury affected, together with a team of experts, Rusedski set about rebuilding just about everything about his game to take the stress off his vulnerable back.

He did not expect miracles, but once he had made up his mind on this drastic and ultimately risky course of action he worked with a total commitment, together with an uncomplaining and unquestioning zeal, that took even Cash by surprise.

"I've proven I am a player again," said Rusedski after the win. " I'm not going to worry about tomorrow or who I play next, because I am going to have days when things are not as good. But now the other guys on the circuit know I am competitive again." Kuerten has himself been troubled again by the back problem of last year and was wearing a brace, together with heavy strapping on his left thigh. But this is to take nothing away from Rusedski, for Guga battled every bit as tenaciously, and was a point away from victory after the British number two doublefaulted twice when 6-5 down in the final set.

So profound was Kuerten's disappointment that he could barely speak. This was his fifth visit to the Australian Open and he has yet to get beyond the second round. It obviously hurt all the more this time because of his newly aquired status as world number one, although the two-times French Open champion had lost three of his previous four meetings with Rusedski and remains clearly uncomfortable facing the left-hander's serve-and-volley tactics.

"I've never met Guga on clay, otherwise my record against him would look a lot different," said Rusedski. "He doesn't meet many left-handers on the circuit who play like I do, but all the same I was not expecting to win."

Rusedski, currently ranked number 65 began the year with defeat in his first match against Tim Henman in Adelaide. He then flew to New Zealand the week before the Australian Open and won three matches on the way to the semi-final of the Auckland tournament before losing to Spain's Francisco Clavet.

In his opening match this week he defeated South Africa's Marcos Ondruska in four less than inspiring sets. He was full of encouraging noises, insisting he was now largely free from pain, although careful to point out that these were early days in the process of restoration and rehabilitation. Then came yesterday's extraordinary win.

His third-round opponent is the 25-year-old Germany qualifier Lars Burgsmuller, who before this tournament had won only two matches at grand slam level and finished last year ranked number 181.

There were no other major surprises yesterday in the men's draw, although Tommy Haas had enough chances to have beaten Lleyton Hewitt, the number seven seed. The unseeded German led 5-0 in the first set, 4-1 in the second set and 4-2 in the third. Yet the 19year-old Australian won them all, the first most remarkably of all by winning seven games in a row.

Defending women's champion Lindsay Davenport crushed unseeded Italian Silvia Farina Elia 6-2 6-1 in the third round.