Lleyton Hewitt [Images] is looming as a serious threat to Roger Federer [Images] at next month's Australian Open, according to the man who has coached both players.

Tony Roche, who recently took over as Hewitt's coach after parting company with Federer this year, believes the fiery Australian still has what it takes to push the world number one.

Hewitt has not won a Grand Slam since Wimbledon in 2002 and has been sliding down the rankings since his days at the top but Roche insists the world No. 21 is not a spent force.

"You're dealing with a world-class player who's been there with that experience," Roche told The Age newspaper on Monday.

Hewitt also won the US Open in 2001 but has made no secret of the fact the title he covets the most is the Australian Open.

He made the final in 2005, losing to Marat Safin [Images], and Roche believes he has the motivation to go one better in 2008.

"It's something that means a lot to him, and he's already got a Wimbledon and a US (Open). So he wants to win the Australian Open," Roche said.

"It's been too long since we've had a winner here. So I'm sure the public are going to get behind him and he'll give it a real shake. There's no question about that."

The Australian Open will be held at Melbourne Park from January 14-27. Hewitt, 26, plans to complete his preparations at the previous week's Sydney International.