Serena seals the comeback of all comebacks

Emotional Williams dedicates her stunning victory to the memory of sister Yetunde

Williams with the women's singles trophy after her stunning victory at the Australian Open

Serena Williams has been written off more times than a banana republic's national debt, but in winning the Australian Open here yesterday she proved that 25 is no age at which to condemn a seven-times Grand Slam champion to the history books.

Williams beat Maria Sharapova, the top seed, 6-1 6-2 in just over an hour with a display of awesome power and self-belief to complete one of the most extraordinary comebacks in the history of women's tennis.

It was Williams' first title of any description since she won her second Australian Open crown here two years ago. Ranked No 81 in the world after playing only five tournaments in the previous 16 months, when injuries and a seeming lack of commitment to her sport left many believing that retirement was imminent, Williams became the lowest-ranked player to win a Grand Slam tournament for 29 years. In the Open era there have been only two other female Slam champions with a lower ranking. Given that Evonne Goolagong and Chris O'Neil won the 1977 and 1978 Australian Opens against weakened fields, Williams' achievement should be regarded as the most remarkable of the modern age.

No wonder she was in tears at the end, particularly when she thanked her family and remembered her sister, Yetunde, who was shot dead four years ago in Compton, the troubled suburb of Los Angeles where Serena and her sister, Venus, learned to play the game.

"Most of all I would like to dedicate this win to my sister, who's not here," Williams told the crowd, her voice cracking. "Her name is Yetunde. I just love her so much. I'll try not to get teary-eyed, but I said a couple of days ago that if I win this it's going to be for her. So thanks, Tunde." Williams, whose mother, Oracene, was here but not her father, Richard, normally goes on court with notes to remind her of her gameplan. Yesterday she carried a single piece of paper on which she had written one word: "Yetunde".

"At every changeover I looked at it and I just thought about how happy she would have been, how much she always supported me," she said. "I just thought about what an amazing sister she was to me. I just said: 'Serena, this has to be motivating. This has to be more than enough to motivate me'. And I think it was."

Like Venus, who missed this tournament because of a wrist injury, Serena is a scrapper who never knows when she is beaten. Some will see her victory as evidence of the underlying weakness of women's tennis, but her return to the top - she will jump 67 places to No 14 in tomorrow's new rankings list - can only strengthen the game. She will play in tournaments in Bangalore and Dubai next month and is already looking forward to the French Open in May.

Williams is probably still some way short of peak condition. She might easily have lost earlier in the tournament, Nadia Petrova and Shahar Peer both having served for the match against her, but has improved with every round. While it is debatable if she has the same mobility that helped her win seven Grand Slam titles between 1999 and 2005, she retains formidable power.

The roof was closed over the Rod Laver Arena (for the fourth women's final in five years) to keep out the rain, but the sky fell in for Sharapova. In her previous 85 matches in Grand Slam tournaments the US Open champion had never suffered such a comprehensive defeat.

Sharapova's serve creaked under the pressure of Williams' assault from the start. The Russian served six double-faults, struggled with her ball toss and saw her second serves, in particular, dispatched with merciless force. In contrast, Williams served beautifully. Her seven aces took her tournament tally to 64, 19 more than any other player and 29 more than Sharapova. What impressed on this occasion was not so much her power but her placement: to keep the ball out of Sharapova's long reach is a feat in itself.

It was a similar story with the two players' groundstrokes. Sharapova never got into any sort of rhythm, while Williams was in the groove from the moment she hit a backhand cross-court winner on the first point. The American went for her shots throughout, hitting 28 winners to Sharapova's 12.

Sharapova had the misfortune to meet Williams just as the American rediscovered her natural game. "I finally played it for the first time this whole tournament," Williams said. "When I'm staying close to the baseline, I'm playing that way, aggressive. That's the way I was raised. My mum and dad taught me to play that game. For some reason, I stay on the baseline. But that was the Serena that I've been trying to showcase for years and years.

"When I'm playing well, it's difficult for anyone on the women's tour to beat me because I have a unique style, a unique game. Tennis is what I think I was born to do."

Williams won 11 points in succession during a blistering start which saw her take the first five games. The fourth game, on Sharapova's serve, was typical. Two ferocious returns forced the Russian into errors and they were followed by two crashing forehand winners, one cross-court and one down the line.

Sharapova was broken in the first game of the second set, failed to take advantage of two double-faults in the second and soon trailed 4-0. The way Williams served out to love in the final game summed up Sharapova's match. She lost the first point after being outgunned in a baseline rally for the umpteenth time before Williams served two aces and then converted her first match point with a backhand winner down the line.

In her moment of triumph Williams threw her racket into the air and fell flat on her back. Returning to her feet, she did a dance of joy before mouthing the words: "Hey, dad, thanks for the advice."

Later, she admitted: "There's always times out there where you think: 'Am I ever going to be looking at another trophy?' Especially since I hadn't won a tournament, let alone a Grand Slam, in a long time. You think: 'Wow, will there be another time?'

"But since day one, my mum and my dad have always been so positive. They never stopped believing in me. That helps me believe in me. Venus as well. I live with her, so I'm with her every day. We always believe in ourselves. You know, it works."