Michael Phelps has immediately turned his attention to the mental and physical challenge of next year's Beijing Olympics after his record-breaking exploits at the World Championships in Melbourne.

The 21-year-old American won his seventh gold medal on the final day of the championships and eclipsed the record of Australian Ian Thorpe, who had held the previous best of six golds at one World Championships. It also matched the major games feat of American Mark Spitz, who took seven gold medals at the 1972 Olympics in Munich.

Phelps had earlier been eliminated from contention for another gold when the American team in the 4 x 100 metres medley relay were disqualified after Ian Crocker jumped into the water before the changeover was complete.

"Fatigue really started setting in three days ago," Phelps said. "At the Olympics, it's going to be even harder, because the amount of pressure, the number of press and everything that goes into the Olympics itself, is more emotionally draining than a World Championships. There is work to be done to get ready for that."

Unsurprisingly given his career achievements so far, Phelps plans to make more history in the pool. "I'm hitting my peak. I have more goals to do, more things to accomplish and I'm not stopping until they are done. I want to be one of the greatest swimmers of all time."

He quickly recovered from the relay setback to set the landmark in the 400 metres medley and smash another world record to boot. The American came home in 4min 6.22sec - beating his previous record set at the Athens Olympics by more than two seconds - to earn his place in the record books.

Liam Tancock was Britain's leading light as he collected a second bronze medal in the men's 50 metres backstroke on the final day. The Loughborough University swimmer, who also collected bronze in the 100 metres backstroke, was beaten by 0.25sec by South African Gerhard Zandberg (24.98sec) with defending champion and world record-holder Thomas Rupprath, of Germany, taking silver.

"It's another medal for me at a World Championships but it's not really the time I was after," Tancock said. "I over-revved my arms a little and didn't achieve what I wanted which was a personal best time. These meets are all about gaining experience for the Olympics and I'm learning all the time. The week has gone well for me and I'm looking forward to getting back in the water and preparing for a strong challenge in Beijing."

Britain's David Davies had to settle for bronze in the men's 1,500 metres freestyle despite being the fastest qualifier. The Welshman lost out to Poland's Mateusz Sawrymowicz (14:45.94) by 5.27sec while Russian Yury Prilukov took silver 1.35sec behind his eastern European rival.

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