London:
Roger Federer was in imperious form as he surged into the Wimbledon quarter finals on Monday as Rafael Nadal hoped to overcome his knee pain to join him in the last eight.
Both defending champion Federer and world number one Nadal entered the fourth round looking to put behind them the problems in their games which saw both of them stretched to five sets in the opening rounds.
And Swiss top seed Federer, who is gunning for a seventh Wimbledon title, blasted away the doubts with a 6-3, 6-2, 6-3 win over Austrian 16th seed Jurgen Melzer on Centre Court.
"I felt great. It was always going to be a tough match against Jurgen," Federer said.
"I found my range and I was playing well and very happy with the way I played. This is a very good win for me.
"I think my form's good now and that's what I really care about.
"I know how to win here's and that's a great advantage for me."
Spanish 2008 Wimbledon champion Nadal is up against France's Paul-Henri Mathieu on Court One.
Nadal has been troubled by a right knee injury and is set to have treatment on it once the tournament ends.
He has to blank out the pain once again when he faces the unseeded Mathieu.
"Roger is in the other part of the draw. I am focused on my part," the 23-year-old said.
"I am focused on the next match against Mathieu and playing well. But Mathieu is going to be a very difficult match."
Britain's Andy Murray will be looking to revive a nation's sporting hopes after England's dismal defeat to Germany in the football World Cup.
The fourth seed faces America's Sam Querrey, who won Queen's, the Wimbledon warm-up tournament.
Querrey, 22, is currently enjoying the best season of his career, winning three tour titles.
The third seed, Serbia's Novak Djokovic, is up against Lleyton Hewitt, the 2002 Wimbledon champion, who won Halle, the other main Wimbledon warm-up.
Hewitt is in dangerous form and no player in the men's draw has notched up more wins on grass than the Australian.
Meanwhile Andy Roddick, three times a beaten finalist here, is up against the unseeded Lu Yen-Hsun, who has made history by becoming the first Taiwanese man to reach the fourth round of a Grand Slam singles.
In an all-French clash, 10th seed Jo-Wilfried Tsonga faces 32nd seed Julien Benneteau.
Swedish sixth seed Robin Soderling takes on Spanish ninth seed David Ferrer for a place in the last eight.
Federer faces the winner of a clash between Czech 12th seed Tomas Berdych and Germany's Daniel Brands, who made it through after Romania's Victor Hanescu pulled out of their third round tie in controversial circumstances.
Hanescu was fined for spitting towards the crowd and not trying as he threw in the towel in the fifth set.
He has since apologised.
"There were people in the crowd that had been insulting me since the beginning of the match," the 31st seed said.
"I lost my control briefly in the fifth set after another insult from someone in the crowd.
"I should never have done that but I am human and I made a mistake."