WIMBLEDON, England(AP) 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 1/2 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.

A wonderful day for the fans,'' said Federer, who beat No. 16 Jurgen Melzer in the main stadium, then observed,Obviously I know every corner of this Centre Court. It helps.''

Serena Williams followed him out there and 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.''

In a matchup between former No. 1s and Grand Slam champions from Belgium who recently came out of retirement, No. 8 Kim Clijsters beat No. 17 Justine Henin 2-6, 6-2, 6-3. Henin slid and tumbled to the grass in the match's third game, jarring her right elbow, and wasn't the same the rest of the way.

Lleyton Hewitt, the 2002 winner at the All England Club, lost to 2008 Australian Open champion Novak Djokovic 7-5, 6-4, 3-6, 6-4, while two-time major finalist Andy Murray - Britain's hope for its first homegrown male champion since 1936 - defeated No. 18 Sam Querrey of Santa Monica, Calif., 7-5, 6-3, 6-4 and is the only man yet to drop a set.

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.'''

It was a tight match, but Groth is far less experienced in these matters than Williams, who advanced to the 31st Grand Slam quarterfinal of her career - 31 more than Groth. At 5-all in the tiebreaker, Groth double-faulted to hand over a match point, then dumped a forehand into the net.

In the other quarterfinals, Clijsters faces No. 21 Vera Zvonareva, who advanced when No. 4 Jelena Jankovic quit because of a back injury; Kvitova plays 80th-ranked qualifier Kaia Kanepi; and Serena Williams meets No. 9 Li Na.

The men's quarterfinal matchups Wednesday will be top-seeded Federer vs. No. 12 Tomas Berdych; No. 2 Nadal vs. No. 6 Robin Soderling in a rematch of this month's French Open final; No. 3 Djokovic vs. Lu; and No. 4 Murray vs. No. 10 Jo-Wilfried Tsonga.

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.

Lu is the only unseeded man left. Indeed, when Djokovic met with reporters after his victory - but while Roddick-Lu was still in progress - he was asked to size up a meeting against the American.

Who could have expected Lu to win? He didn't even earn a single break point against Roddick through the first three sets, yet led by virtue of being more solid in the match's first two tiebreakers.

Through three sets I was playing horrendously, I mean really, really badly,'' Roddick said.I was trying to think of how to put balls in the court. I think the fifth set was probably the best set that I played ... but when you dig yourself a hole, it's tough to get out.''

By the end, Roddick had won more total points, 199-196. But Lu served much better than he had in their past matches, winning 101 of 124 points in his service games and saving 7 of 8 break points, including 3 of 3 in the final set.

He had one break point in the fourth set, which Roddick saved, and one in the fifth, at 8-7. Roddick began the last game by missing a forehand wide, then shanked another one. At 30-all, Roddick hit an apparent ace, but Lu challenged the call, and the replay showed it was a fault. Roddick's second serve came at 98 mph, and Lu drilled a return that forced Roddick into a forehand error.

Suddenly, it was match point, and Lu got back a 133 mph serve, then smacked a winner for his first victory over a top-10 opponent since defeating Murray in the first round at the 2008 Beijing Olympics.

Lu sat in his sideline chair, buried his face in a towel, and immediately thought of his late father, who used to take him to tennis lessons. After Lu became the first man from Taiwan to reach the fourth round at a Grand Slam, his mother and brother went to the hill where his father is buried to give him the good news.

After Monday's victory, Hordorff told his charge: ``Now your family can go again, and tell him that you're in the last eight.''

Roddick, meanwhile, was left to stew about what has to be one of the most disappointing losses of his career, given the tournament, the round and the opponent.

He deserved to win more than I did,'' Roddick said.That's for sure.''