Serena Williams is asked how she would write the story of her Australian Open victory. She pauses for a moment before coming up with a line that does the job nicely. "Serena Williams - she's back. And this time to stay."

If the second half of that sentence is open to question when we are talking about a player who turned up for only four events during the 2006 season, the first is indisputable.

The destructive force she brought to bear in Saturday's victory against Maria Sharapova proved that the string of stumbling, flawed performances which she put in en route to the final were merely a misleading prelude to the return of the real Serena Williams, the one who dominated women's tennis in 2002 and 2003.

Sharapova will be crowned No.1 in the world rankings this morning; Williams will be back up to 14 after starting the Australian Open ranked 81, but for an hour and three minutes on Saturday, it was Williams who looked like the best player on the planet once again.

Sitting with a small group of journalists a couple of hours later, 25-year-old Williams is in cheerful, if contemplative mood. Her professional persona - all pumped up aggression during the match, followed by conceited showboating afterwards - is not easy to like. In person she is warmer and a little more human, so that it is easier to believe her when she reveals that the constant jibes about her weight and lack of conditioning in recent years hurt her very deeply.

"The ones that I wasn't fit hurt the most. I felt that I was really fit. I feel that because I'm larger in some areas than other girls, that I don't have a flat chest, I don't have a flat ass, I felt that people said I wasn't fit. But I was looking in the mirror today and I was looking at myself and I was like, Am I not fit or am I fit or what?' I mean, my waist is like 28 inches or whatever, which is really small. I just couldn't quite figure it out on that one.

"After the two longest matches that I played, I was up practising at seven the next morning. I was ready for the whole tournament. I was never not ready. But I feel that I could be better."

It is that last statement that ought to send her peers scuttling back to the practice court and the gym, for the thought of Williams actually playing better than she did against Sharapova is a terrifying thought. Away from the press conference stage, where Williams is apt to grandstand and obfuscate, she is more honest about what represents a realistic schedule for her this year.

No, she will not play as many events as most top 20 players do; but she will play more than she has done over the last two seasons.

Reading between the lines, she will play the events she is interested in winning. "You know what, I've answered every critic that I've had. I plan on keeping answering them when they say I'm not going to play that much," she says.

"Granted, I'm not going to play 32 tournaments this year, I'm not going to play 22. But I'm going to play the ones that I'm going to play - and there are not going to be that many - but I'm going to be serious about each and every one. That's my goal."

Williams does not like to lose. She tells a story, which both illustrates her inability to take defeat on the chin and goes some way to explaining the iron-clad determination that allowed her to pull off such a remarkable victory at Melbourne Park.

Having lowered herself to a minor warm-up event in Hobart three weeks ago, a fourth tier of WTA Tour event and thus the lowest strata of tournament she had ever played, Williams was mortified at losing to German journeywoman Sybille Bammer in the quarter-finals. She went for a run to let off some steam.

"I was just running and running and I was just so mad, so mad because I felt like, I'm never going to win another title again, I can't even win a tier IV event'. It was just like a scene from Rocky."

After working up a sweat, she found herself with a raging thirst and went into the only place she could find to get some water, a local pub, and brandished her Platinum American Express card at the - presumably - startled lady behind the counter.

She ended up buying two bottles of water for the pub's credit card minimum of $30 but says she learned a valuable lesson, one which may come in handy for the rest of what could be a momentous 2007.

"The next time I lose my mind, I'm taking a bottle of water with me."