Henman is hoping for happy birthday returns

"I felt really good, my energy levels were fine and I felt like I could keep playing." The back injury has been hampering Henman throughout the tournament but has not stopped him securing three hard-fought victories.

"It's actually when I stop that it comes on," he said. "I found towards the end, when I was sitting down between games, my back was getting pretty stiff.

"We sit down for 60 to 90 seconds and I find that for the first couple of serves when I come back out I feel so stiff and there isn't any flexibility.

"I struggled and got off to some bad starts in my service games in the fifth set but I kept fighting and that's the most important thing."

By way of contrast, it has been plain sailing so far for Andy Roddick and Lleyton Hewitt.

Hewitt, the 2001 champion, routed Spaniard Feliciano Lopez 6-1, 6-4, 6-2 and there is no other seed in his way until the semi-finals.

"I feel good at the moment," the Australian said. "In the Slams this year, I feel like I've played pretty well and I've lost to the eventual champion each time."

Second seed and defending champion Roddick also cruised into the fourth round with a 6-1, 6-3, 6-3 destruction of Argentina's Guillermo Canas.

The American's unbelievable serving continued with 21 aces and no double faults. "I played well," said Roddick, whose serve has been broken only once in three rounds.

Roddick is getting used to some fast starts, losing a total of one game in the first set of his first three matches. He now meets 18th seed Tommy Robredo, of Spain, who defeated Austrian qualifier Alexander Peya 6-3, 6-3, 6-2.

Jennifer Capriati's clash with Serena Williams is the pick of today's fourth round clashes in the women's singles.

Third seed Williams was too strong for Switzerland's Patty Schnyder in the previous round, winning 6-4, 6-2. Capriati defeated 12th seed Ai Sugiyama, of Japan, 7-5, 6-2. "I like playing Jennifer a lot," said Williams, who has a10-6 record against her fellow American. "She brings out the best in me."

They will be facing each other for the third Grand Slam event in succession. Capriati won in three sets in the quarterfinals of the French Open and Williams responded with a straight-sets last-eight triumph at Wimbledon.

Amelie Mauresmo is already through to the quarter-finals after a 6-4, 6-2 victory over Francesca Schiavone, of Italy. The second seed now meets sixth seed Elena Dementieva, of Russia.