Reputation and national pride will be on the line when Roger Federer and big-serving Andy Roddick emerge on Centre Court for their much-anticipated semi-final on Friday.

The instant defending champion Lleyton Hewitt was felled by Croatian Ivo Karlovic on the first day of the championships, the Federer-Roddick showdown was the one people wanted to see.

But before the duo can do battle, Mark Philippoussis will want to complete his journey back from the depths of an injury-ravaged career as he bids to reach his first final at the grasscourt Grand Slam against France's Sebastien Grosjean.

Possessing an effortless all-court game, Federer has been touted as a future Wimbledon champion from the moment he snapped Pete Sampras's 31-match winning streak at the All England Club in the fourth round in 2001.

But until this week, Swiss Federer had failed to get beyond the fourth round at any of the slams since reaching the quarter-finals at Roland Garros and Wimbledon two years ago.

"People have been talking about me taking the next step. It's all about giving yourself the opportunities and taking them. Now I'm going to try and go further," said Federer, who will be looking to extend his 3-0 unbeaten streak against the American.

"I've always had my chances in grand slams to do well but I just didn't take that opportunity and that was my problem. But here I am finally in the semi-finals and now hope to take my chance."

While Federer was tagged a big-stage flop, Roddick has also failed to live up to the hype.

The 20-year-old was supposed to be the new torchbearer for American tennis as Andre Agassi and Pete Sampras headed towards the twilight of their illustrious careers.

More than two years after bursting on the scene, Roddick was still trying to emerge from the shadows of his 30-something American rivals.

WORST SHOWING

But a year after Americans suffered their worst showing at Wimbledon in the Open era, when none made it through to the second week, Roddick has thrown down the gauntlet to his challengers and has been installed as the bookmakers' favourite.

"I have to play probably the best player not to have won a Grand Slam so I'll have to take care of that," said the fifth seed.

"He won in Halle and I won Queen's so we're both on rolls. I think we both have an air of confidence right now and the match should be a good one."

For Philippoussis, the only former Grand Slam runner-up to feature in the semi-finals, victory on Friday would be a massive boost after his long battle with injury.

"After the three surgeries it's been a long road back but after all the hard work, it pays off and makes it all worthwhile at the end," said the Australian, who has undergone three knee surgeries since 1999.

"When you're down and out and come back, it's always that much sweeter."