Olympic and world champion Jeremy Wariner is convinced he will break Michael Johnson's long-standing 400 metres world record at this year's Beijing [Images] Olympics [Images], if not before.

The 24-year-old Texan has dominated the men's one-lap event for the last four years and the world mark of 43.18 seconds set by Johnson, his mentor and agent, at the 1999 world championships is firmly in his sights.

Wariner brushed aside questions about last month's split with his long-time coach Clyde Hart and said he is totally focused on the Beijing Games.

"I'm looking forward to defending my title and hopefully breaking the world record," he said on Monday.

"Honestly, if I haven't broken it before the Olympics, I know I can break it at the Olympics."

"There'll be a lot of energy at the Olympics and I have a lot of Asian support so I'm looking forward to it."

PERSONAL BEST

Wariner, whose personal best was the 43.45 seconds he ran to retain his world title in Osaka last year, said Johnson is helping his bid to erase the nine-year-old mark from the record book.

"He knows I could break the record but he still gives me advice," he said.

"He sees flaws in my race and he tells me, 'you've got to work on this'. He tells me good things and bad things about my race and helps me improve on those.

"My race is not 100 percent perfect and it will never be, there's always going to be a little flaw in my race I can work on.

"Mentally, I'm there and physically I'm there, I've just got to put everything together at the right time."

Wariner, in Beijing on a trip organised by his personal sponsor Adidas, refused to go into details about the split with Hart over a contract dispute.

"It's between coach Hart and myself," he said. "I'm happy with where I'm at with my new coach Mike Ford. The speed is there ... I know what I need and I know what I don't need."

Wariner said he is preparing to make his 2008 debut in Australia next week and would be better positioned to say what kind of shape he is in after that.

"But I think I'm ahead of where I was at in previous years," he said.