By Piers Newbery
BBC Sport at Wimbledon
Roger Federer will take on Lleyton Hewitt in a mouthwatering quarter-final after the pair came through their fourth-round matches.
Federer had a routine win over Ivo Karlovic on Court One, while Hewitt needed four sets to beat Carlos Moya on Centre Court.
"Against Hewitt, it will be extremely tough because he's won here in the past and everyone knows the matches we've had," said Federer.
Defending champion Federer is still yet to drop serve in the tournament after easing through 6-3 7-6 (7-3) 7-6 (7-4).
Karlovic was broken at 2-3 in the first set as Federer finally got to grips with the 6ft 10in Croat's huge serve.
Neither man could fashion a break point in the second set but Federer cruised through the tie-break and repeated the trick in the third.
"Someone will have to play at a very high level to beat me and so far they haven't been able to do that but that can change very quickly," said Federer.
"I don't remember playing bad tennis and that's good looking ahead to the rest of the tournament."
A fired-up Hewitt confirmed he is a serious title contender with a hard-fought 6-4 6-2 4-6 7-6 (7-3) win over Moya.
Seventh seed Hewitt looked in control at two sets up but could never relax, and Moya broke twice in the third.
Moya fought back again in the fourth and saved a match point before Hewitt finally finished the Spaniard in the tie-break to set up a clash with Federer.
"It's going to be tough - he's the form player and the defending champion," said Hewitt.
"I'm looking forward to it but I'll have to step up a gear. I've got to go out and worry about my game.
"We've had some tough matches in the past and I don't expect it to be any different this time."
Sebastien Grosjean kept up his fine run of form on grass with a demolition of American Robby Ginepri on Court Two.
The Frenchman, who is seeded 10th and bidding to improve on last year's semi-final appearance, won 6-2 6-2 7-6.
Also in the top half of the draw, Grosjean faces Florian Mayer next, after the German beat Joachim Johansson 6-3 6-7 (5-7) 7-6 (7-5) 6-4.
"My serve is a little bit faster on grass than on clay and I can use the slice serve more," said Grosjean.
"I also return well so that helps me a lot on grass and I just try to enjoy being on court.
"I don't know anything about my next opponent, Mayer, but I will just focus on my game and not him and I know what I have to do."