WIMBLEDON, England — Andy Roddick never did figure it out.
The big serve that kept kicking up chalk dust, the cruelly low-bouncing ground strokes, the slippery volleys that would skid past a lunging Roddick — all of it was just too perplexing until the three-time Wimbledon finalist who was seeded fifth trudged off Court 2 with a soggy towel draped around his slumped shoulders.
Yen-Hsun Lu, a 26-year-old son of a chicken salesman from Taipei, Taiwan, who said he gave himself little hope after the fourth set, beat Roddick 4-6, 7-6 (3), 7-6 (4), 6-7 (5), 9-7 Monday in the fourth round.
Along with the exit of 18th-seeded Sam Querrey, who lost more predictably to fourth-seeded Andy Murray of Scotland 7-5, 6-3, 6-4, there are, for the fourth time in the last 10 years, no American men in the Wimbledon quarterfinals.
For the women, it's a different story.
Top-seeded and defending champion Serena Williams prevailed in a compelling first-set tiebreak and overpowered 16th-seeded Maria Sharapova 7-6 (9), 6-4, while Venus Williams, a five-time Wimbledon champion and seeded No. 2, advanced to the quarterfinals with a 6-4, 7-6 (5) win over Jarmila Groth.
Also into the quarterfinals is eighth-seeded Kim Clijsters, who beat 17th-seeded Justine Henin 2-6, 6-2, 6-3.
In the other major upset of the day, Petra Kvitova of the Czech Republic steamrolled third-seeded Caroline Wozniacki of Denmark 6-2, 6-0.
But it was the emotional Lu who made the biggest impact of a busy day when all 16 men and 16 women in the tournament played fourth-round matches.
"I couldn't imagine this moment," Lu said. "And from when I lost the fourth set, I thought it was a better chance for him. Right now, I didn't think this could happen."
The 27-year-old Roddick hadn't lost to Lu in three previous meetings. Roddick is 115-37 lifetime in Grand Slam matches; Lu is 10-18. On grass Roddick is 73-17; Lu is 12-17.
The numbers said Roddick would be the one to step up in the fifth set, to conquer whatever it was about Lu's serve that had kept him befuddled, to put into play his experience, to let himself be fueled by the crowd that kept yelling, "Come on, Andy." But Lu allowed none of that to happen.
Roddick called his play "horrendous" in the first three sets and said if he knew why, "I probably would have figured it out, right? It didn't feel good. It didn't feel clean."
Serena Williams had no such complaints about her game, not after 19 aces and 31 winners.
"I served well today," Williams said. "She returned really well, and it forced me to serve well."
Sharapova agreed.
"If it was not for her great serving," she said, "I had a real good look at winning the match."
dpucin@tribune.com