Roger Federer was in imperious form as he surged into the Wimbledon quarter-finals yesterday.
The defending champion entered the fourth round looking to put behind him the problems which saw him stretched to five sets in the opening rounds.
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.
Serena and Venus Williams battled their way into the quarter-finals as well as the first big seeds in the women's event tumbled.
The sisters had a fairly easy ride to the round of 16, dropping no sets and few games. But they were forced to fight in the fourth round, which saw Caroline Wozniacki, Jelena Jankovic and Maria Sharapova knocked out.
Meanwhile, Kim Clijsters beat Justine Henin in the battle of the Belgian comeback queens.
Federer said he is back to the top of his game.
"I felt great. It was always going to be a tough match against Jurgen," he 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."
Federer faces Tomas Berdych in the quarter-finals after the Czech 12th seed came from behind to beat Germany's Daniel Brands 4-6, 7-6, 7-5, 6-3.
Defending champion Serena was taken to a first-set tie-break by Sharapova. The Russian 16th seed led 5-3 and had three set points but a double fault at 9-9 proved costly and Williams dug in to win the first set 7-6 (11-9). Williams then broke Sharapova to take the second set 6-4.
Older sister Venus, a five-time Wimbledon champion, saw off a gritty fightback from Jarmila Groth to go through.
Venus was given a rough ride by the determined, unseeded Australian in a 6-4, 7-6 win on Court Two. Williams now faces Tsvetana Pironkova in the quarter-finals. The Bulgarian beat Marion Bartoli 6-4, 6-4 yesterday.
Eighth seed Clijsters came from behind to beat her old friend Henin to keep alive her bid to win Wimbledon for the first time. Henin won the first set 6-2, but Clijsters won the second 6-2 and the third 6-3 to go through.
Clijsters now faces Russian 21st seed Vera Zvonareva, who was 6-1, 3-0 up against fourth seed Jankovic when the Serb withdrew. But third seed Wozniacki was also humbled, losing 6-2, 6-0 to Petra Kvitova.
China's Li Na reached the last eight for the second time as she beat skilful Polish seventh seed Agnieszka Radwanska 6-3, 6-2. Li faces Serena Williams in the quarter-finals.
Fourth round results: (men) Djokovic bt Hewitt 7-5 6-4 3-6 6-4; Tsonga bt Benneteau 6-1, 6-4, 3-6, 6-1; Murray bt Querrey 7-5 6-3 6-4; Soderling bt Ferrer 6-2 5-7 6-2 3-6 7-5; Hu bt Roddick 4-6 7-6 7-6 6-7 9-7; Nadal bt Mathieu 6-4 6-2 6-2.