Serena on her best behaviour for SW19

Nine months after her foul-mouthed outburst at a US Open line judge cost her a fine of $82,500 (about £56,000), Serena Williams is promising to be on her best behaviour when Wimbledon starts next week.

"I've demolished a few rackets here, but I'll try not to do that this year," the defending champion said yesterday after her return to the All England Club. "I didn't break any at the French Open. I think that was my first Slam in years where I haven't done that."

Williams, whose fine will be doubled if she offends again at a Grand Slam event over the next two years, did not think the incident in New York would affect her relationship with the Wimbledon crowd. "It was a while ago," she said. "I think people can really understand my passion for the game and how much I love to play and how much I love to just be out there competing on the court."

After losing in the quarter-finals of the French Open Williams spent the best part of a fortnight back home training in the Florida heat. "I've just hit on grass here today and yesterday," she said. "There aren't too many grass courts in the US, so I just adopt Andre Agassi's method. I read once about how he never practised on the grass, he just played on hard courts."

Is she ever tempted to miss a training session? "Every day I wake up and think: 'On no, I've got to practise again.' I feel like Bill Murray in "Groundhog Day". But once I get on the court I rediscover my desire.

"As an athlete, especially when you're a professional, you have to think to yourself: 'If I'm not practising then someone else is.' You might think you could just go home, but that would always be at the back of your mind. The only way to make that constant noise in the back of your head go away is to go out and practise.

"When you don't enjoy doing something I think you shouldn't continue to do it, but I'm healthy and I have a great opportunity in front of me. I feel that when you're given a chance and an opportunity to do something that you love or that you're good at then you should definitely take it."

Williams said she had been following the World Cup closely, watching "every match, every day". She said her "football obsession" started on a previous trip to Britain and extended to a trip to Stamford Bridge to watch Chelsea play. The World Cup final takes place the weekend after Wimbledon ends and Williams said she was organising a party at her home to watch it.

Would she be requesting start times at Wimbledon that did not clash with World Cup matches? "The problem is that I have so many teams I'm rooting for," she said. "I would have so many requests that I would never play."