By Ian Westbrook
BBC Sport at Wimbledon
Andy Roddick marched into a last-eight clash with Sjeng Schalken by seeing off Alexander Popp 7-5 6-4 6-4.
Roddick, who has not dropped a set in this year's Championship, snatched the first set by winning only the second break point.
Serve continued to dominate in the second set and once again Roddick gained the only break in the 10th game.
Popp broke Roddick when he was serving for the match at 5-3 in the third but the second seed broke back to seal victory with his fourth match point.
Roddick admits it will be strange facing Schalken, the player whose life he helped save in a fire.
"This is a much better position to be in!" joked Roddick, who help shepherd a number of people to safety when the blaze broke out in a Rome hotel in May.
"It's weird how things work. We knew we'd play each other again but once you get on the court you try to forget it.
"I'm sure we will be focused on trying to win a Wimbledon quarter-final."
Mario Ancic set up a possible clash with Tim Henman in the quarter-finals after opponent Xavier Malisse was forced to retire from their match.
Malisse, who came into the tournament with a back injury, was treated for a similar problem during the match.
Ancic was 7-5 3-1 up when the match was halted and is in the last eight of a Grand Slam for the first time.
It was a disappointing end for Malisse, who reached the semi-finals here just two years ago.
"I have been struggling with a problem in my lower back since the French Open," said Malisse.
"Three matches in two days - it's probably too much. I've felt it since the first round on the high balls, but this is the most painful it has been."
Dutchman Sjeng Schalken punched the air with delight when he sealed his last- eight berth with a 6-2 7-5 3-6 6-2 victory over Vince Spadea on Court Two.
Number 12 seed Schalken served up three aces and made 86% of first serves as he broke Spadea twice in the opening set.
Spadea cut down the number of unforced errors in the second set and finally made his efforts count in the third.
But the mistakes crept back in the next set, ensuring Schalken made the quarter finals for the third consecutive year.