WIMBLEDON, England - Andy Roddick's mood was subdued, his words curt.

Once again, he's leaving Wimbledon without the champion's trophy. Only this time, Roddick heads home much earlier than a year ago - and after being beaten by a far-less-accomplished opponent.

The No. 5-seeded American erased an early deficit to even his fourth-round match against 82nd-ranked Yen-hsu Lu of Taiwan, then got broken for the only time all day in the very last game and lost 4-6, 7-6 (3), 7-6 (4), 6-7 (5), 9-7 despite hitting 38 aces Monday.

"It never gets easier," said Roddick, a three-time runner-up at Wimbledon. "Of course I'm going to be (ticked) off when I wake up tomorrow. I mean, if you got fired from your job, you probably wouldn't wake up the next day in a great mood."

This one sure looked like a mismatch going in, and not only because Roddick won all three previous meetings in straight sets.

Roddick, after all, is a former No. 1 who won the 2003 U.S. Open and played in four other major finals, losing each to

Roger Federer, including 16-14 in the fifth set at the All England Club in 2009.

And Lu? The guy arrived last week with a 6-18 career record in majors, including five consecutive first-round exits. He also lost in Wimbledon's first round the past four years. So even he had doubts as the match stretched beyond 4? hours.

"Fifth set, I don't believe I can win, because he's (a) better server than me," Lu said. "But I just tell myself, 'Even (if) I don't believe, I have to fight.'"

He pointed to the sky after ending the match with a forehand passing shot, dedicating the victory to his late father, a chicken farmer who died in 2000.

Lu's coach, Dirk Hordorff said: "Sometimes he's mentally not strong enough. But today he showed he was strong enough."

The second Monday at Wimbledon is one of the great spectacles in tennis, with all 32 remaining men and women in action, and there was quite an array of stars spread around the grounds. With the temperature moving into the 80s, and a cloudless sky, past Wimbledon champions Federer, Rafael Nadal and the Williams sisters all played - and won in straight sets.

Serena Williams pounded 19 aces in her 7-6 (9), 6-4 victory over 2004 champion Maria Sharapova.

"I had a few looks at her serve," Sharapova said, "but even when you had a good look, and the ball's coming at you in the 120s (mph), it's pretty tough to do much with it."

Lu's victory over Roddick was Monday's most significant surprise, by far, but it wasn't the only one.

The 62nd-ranked Petra Kvitova knocked off No. 3 Caroline Wozniacki, last year's U.S. Open runner-up, 6-2, 6-0; while No. 82 Tsvetana Pironkova eliminated No. 11 Marion Bartoli, the 2007 Wimbledon runner-up, 6-4, 6-4.

Kvitova and Pironkova each reached her first major quarterfinal. On Tuesday, Pironkova takes on five-time Wimbledon champion Venus Williams, and the 22-year-old Bulgarian is not likely to be too intimidated: She beat the American at the 2006 Australian Open.

The older Williams sister picked up a 6-4, 7-6 (5) victory Monday over 92nd-ranked Jarmila Groth, but this was no easy day of work. Williams showed up late at the office, strolling out at 12:09 p.m. for their scheduled noontime match, saying later she expected to be escorted to remote Court 2.

"I was waiting on someone to get me. No one came. So eventually I just came out," said Williams, who twice broke when Groth served for the second set. "I saw everyone else leave. I thought, 'OK, time to go.'"

Nadal, the 2008 champion who was forced to five sets the previous two rounds, breezed past Paul-Henri Mathieu 6-4, 6-2, 6-2, showing no sign of being hampered by his bothersome right knee. Soderling edged No. 9 David Ferrer 6-2, 5-7, 6-2, 3-6, 7-5 to make the Wimbledon quarterfinals for the first time.