Roddick stunned as Lu holds his nerve to book quarter-final slot

The world No 82 held his nerve in a five-set thriller on Court Two to win 4-6 7-6 (7/3) 7-6 (7/4) 6-7 (5/7) 9-7 in four hours and 36 minutes.

Roddick lost a classic final to Roger Federer last year but could not shake off Lu, who will face Novak Djokovic in the quarter-finals tomorrow having never previously gone past the second round at Wimbledon.

Although Lu had not dropped a set Roddick was expected to sweep past him and into the last eight.

Until yesterday, beating Andy Murray in the Olympic Games two years ago was Lu's greatest achievement, but this particular victory on the Wimbledon grand slam stage surpasses that.

He had played Roddick three times previously, losing all three including defeats in consecutive tournaments at Indian Wells and Memphis earlier this year.

Afterwards, he admitted he had even surprised himself by pulling off such an unlikely shock victory.

"Even now I'm thinking it's a dream," Lu said. "I couldn't imagine this moment now.

"I probably need time to clear my mind and calm down to see what's happened.

"From the beginning I just told myself to fight. When I lost the fourth set I thought it was a better chance for him so I told myself to stay in the match, and finally I got the chance."

Roger Federer enjoyed a composed afternoon in the sunshine as he defeated Jurgen Melzer to reach the last eight.

After struggling through his opening two matches at this year's Championships, the defending champion posted his second straight-sets win in succession as he outclassed Melzer 6-3 6-2 6-3.

The six-time champion will meet Tomas Berdych in the last eight after the Czech fought back from a set down to see off Germany's Daniel Brands 4-6 7-6 (7/1) 7-5 6-3.

Rafael Nadal eased any concerns over his fitness with a 6-4 6-2 6-2 victory over Paul-Henri Mathieu on Court One to set up an eye-catching quarter-final with sixth seed Robin Soderling, who was pushed hard by ninth seed David Ferrer before clincing a 6-2 5-7 6-2 3-6 7-5 win.

Serbian third seed Djokovic is also through after he fended off the challenge of 2002 champion Lleyton Hewitt in four sets.

Hewitt, the 15th seed from Australia, had defeated Federer in the final of the warm-up event in Halle ahead of Wimbledon, but succumbed to a 7-5 6-4 3-6 6-4 loss.

"It could have gone either way but I played the right shots at the right time and I'm just very happy to get through this one," said Djokovic.