LONDON >> Garbine Muguruza's first major tournament as a reigning Grand Slam champion didn't last long.
Less than a month after winning the French Open, the second-seeded Spaniard was beaten in the second round of Wimbledon on Thursday by a Slovakian qualifier ranked No. 124.
In the biggest upset of the tournament so far, Jana Cepelova beat a listless and mistake-prone Muguruza 6-3, 6-2 on Court 1 in less than an hour to reach the third round at the All England Club.
Muguruza was one of 11 seeded women's players eliminated on Thursday, a day that also saw 10 American men and women win first- or second-round matches as the tournament got through a full day without any rain delays following two days of wet weather.
Muguruza looked like a shadow of the player that reached the final last year, where she lost to Serena Williams, and beat Williams in the final at Roland Garros this month for her first major championship.
"My energy was missing a little today," Muguruza said. "From yesterday I felt a little bit tired. During the match and after the match, I'm like, 'Tough day today, empty today."'
The Spaniard sprayed ugly shots all over the court and finished with 22 unforced errors, compared to just nine winners. Cepelova had a first-serve percentage of just over 40 percent, but still outplayed Muguruza with 14 winners and 12 errors.
"She played great, no fear, trying a lot of stuff that was working," Muguruza said. "But my energy wasn't there. I was trying but it didn't work at all."
Cepelova, Slovakia's No. 5 female player, had to win three matches in qualifying to make it into the main draw. It's not the first time she's knocked off a top player: Cepelova ousted Simona Halep in the first round at Wimbledon last year, also on Court 1, and beat Serena Williams at a tournament in Charleston in 2014.
"Last year I beat Halep on the same court and I had great memories," the 23-year-old Cepelova said. "I am so happy."
The last time a second-seeded woman lost at Wimbledon before the third round was in 2013, when Victoria Azarenka was beaten in the second round.
The second-seeded men's player fared much better Thursday, as Andy Murray swept to a 6-3, 6-2, 6-1 victory on Centre Court over Lu Yen-Hsun of Taiwan.
Murray, the 2013 champion, fell behind 1-3 in the first set, but settled down, took control and dropped only three more games the rest of the way, breaking the 76th-ranked Lu seven times.
Muguruza was nearly joined on the sidelines by No. 3 Agnieszka Radwanska, who saved three match points before coming back to beat 18-year-old Croatian Ana Konjuh 2-6, 6-4, 9-7.
Radwanksa, the 2012 runner-up at Wimbledon, saved one match point at 5-3 in the third set and two more at 5-4. On the third match point, the 103rd-ranked Konjuh stroked a forehand that hit the top of the net tape, popped up and fell back onto her side of the net.
At 7-7, Konjuh stepped on the ball with her right foot as she chased in vain for a drop shot. She hopped to the side of the court and dropped to the ground, sobbing in pain.
Konjuh took a medical timeout, and a trainer taped her foot and ankle. She resumed the match, but was clearly hobbled, and Radwanska quickly closed out the contest.
No. 4 Angelique Kerber and No. 5 Halep advanced, while No. 14 Samantha Stosur was knocked out 6-4, 6-2 by 2013 runner-up Sabine Lisicki.
Dominic Thiem, seeded No. 8 and considered one of the rising stars in the men's game, became the highest seeded male player ousted so far this week. The 22-year-old Austrian lost to 64th-ranked Jiri Vesely of the Czech Republic 7-6 (4), 7-6 (5), 7-6 (3).
The second-round match had only two breaks of serve, one by each player in the first set. Thiem reached the semifinals at the French Open and won a grass-court warm-up in Stuttgart. But it was Vesely who came up big in all three tiebreakers.
Five-time champion Venus Williams led a parade of Americans picking up victories.
The 36-year-old Williams, the oldest player in the women's draw, needed nearly 21/2 hours to get past 20-year-old Greek qualifier Maria Sakkari 7-5, 4-6, 6-3.
The U.S. men's winners included John Isner, Sam Querrey, Donald Young, Jack Sock and Steve Johnson. Joining Williams among the women were Sloane Stephens, Madison Keys, Coco Vandeweghe and Julia Boserup.