Men's Singles Semi-finals previewFor the first time since 1993 all four semi-finalists at Wimbledon are current or former Grand Slam champions. Roger Federer has four titles, Lleyton Hewitt, his opponent today, has two, and Thomas Johansson and Andy Roddick one each. Three of those players also reached the semi-finals of the first Grand Slam of the year in Melbourne, Federer, Roddick and Hewitt.

The winner in Australia, Marat Safin, departed from London in the third round.

Federer and Roddick, who go into their matches as favourites and number one and two seeds, respectively, will be looking to extend the three-year streak of a winner of a pre-Wimbledon title grass court title going on the win Wimbledon itself. Federer won at Halle and Roddick the Queens tournament.

Roddick currently leads Sweden's Johansson 2-0 in their head-to-head meetings, the last in Bangkok last year when he won on hard court in two sets and prior to that at Wimbledon in 2001 in the then 18-year-old's first ever match on Centre Court.

Eight years younger than his opponent, Roddick's hopes of reaching the final for the second year running is clearly an easier task than that of Hewitt.

But the American, although he disputes it, has still not shown that his game is anything more than power on serve and off the forehand. Still, Roddick has used the weapons wisely and is not surprised to be meeting the Swede at this late stage.

"I'm not very surprised. He's the type of guy, when he starts playing well, he plays really well. He's won titles on this surface before, I'm not super surprised," said Roddick.

The same can be said for the title holder. Federer's meeting with Hewitt will hinge on how Hewitt serves. If he can hold serve and squeeze the world number one he has a chance.

They both know each other's game well but the stinging statistic of Federer having beaten Hewitt in their last seven meetings indicates a Swiss bias.

"We've played on so many occasions now that I think we know each other's games so well. We don't need to have spies around because we're not going to change our games very much," said Federer.

"He's beaten me enough to believe in his chance. He knows. And on grass I think anything can happen against him. He knows how to win the title here."

From Hewitt's point of view Federer, who has dropped just one set in his six matches, represents an unusual challenge. It is not often the Australian steps on court and realises he will lose unless he can raise his game a level from where it is now or unless Federer misfires.

"I'm not sure what the key is," said a candid Hewitt, when asked how he could win the match. "Have to try and find something over the next couple of days. He's obviously the best player in the world for a reason. He's really taken the game to another level over the last couple of years."