WIMBLEDON, England — For the many highs and lows her young career has had, Wimbledon has remained something of a constant for Petra Kvitova, who has reached the quarterfinals or better in each of the last five years and won the tournament twice, in 2011 and last year.
But Saturday afternoon, what had looked like a routine stroll for the second-seeded Kvitova to her 10th consecutive victory at the tournament was derailed in a 3-6, 7-5, 6-4 defeat by Jelena Jankovic of Serbia, the No. 28 seed, on Centre Court.
With her propensity to follow poor play with brilliance and brilliance with more bafflingly bad play, few Kvitova losses can be considered complete shocks. But Wimbledon has been a sanctuary, allowing Kvitova, a free-swinging Czech left-hander, to summon her best time and time again. Kvitova did not play poorly against Jankovic, a veteran who was once ranked No. 1, but she allowed Jankovic to regain a foothold in a match that seemed over when Kvitova led by 4-2 in the second set.
While grass is Kvitova’s best surface, Jankovic considers it her worst, but on Saturday she played with atypical abandon, taking strong swings at returns that forced errors from Kvitova to level the match and force a third set.
“Tough to explain; if I know what happened, I’m going to tell you,” Kvitova said of the reversal. “But really, I’m not really sure what happened out there. I was kind of up in the second set. Suddenly, I felt like she’s coming back, playing a little bit aggressive. And suddenly, from my side, I didn’t have answers for it.”
The lack of answers left Kvitova similarly at a loss to describe her disappointment at the defeat.
“Not to be in the second week of the favorite tournament for me is really sad,” she said. “I don’t really know what I can say — that’s it.”
Jankovic, an effusive player with one of the least effective poker faces in the sport, beamed as she sat on her chair as Kvitova took a lengthy break before the third set to change her outfit and regroup mentally. Jankovic remained positive through the final set, as she held serve with relative ease five times and capitalized on her first match point in the 10th game.
When a Kvitova serve curled into her stronger backhand wing, Jankovic pounced, hitting a deep drive down the line and forcing a backhand error from Kvitova that fell meekly into the net. Jankovic collapsed to her back, swung her feet over her face in joy, raised her arms in the air and jogged to the net, her upper back still caked in dirt from the battered ground behind the baseline.
Jankovic had cleaned herself off by the time she entered her post-match news conference, but her smile remained glued on.
“I’m glad I was able to stay strong and positive,” she said. “I was down a set and a break in the second, and I was able to just stay calm. I just played one point at a time and held my ground and won that second set. After that, I knew I could do it.”
Jankovic’s surprising stay into the second week of the tournament has been matched by several other unexpected faces in the fourth round, particularly on the bottom half of the draw. None of the eight women have ever won a Grand Slam; the highest seed remaining is No. 5 Caroline Wozniacki, followed by No. 13 Agnieszka Radwanska, Jankovic’s next opponent. Those three women are the only ones on that side of the draw to have reached a Grand Slam final, a feat Wozniacki has accomplished twice.
The women on the top half of the draw have combined to win 34 Grand Slam singles titles: top-seeded Serena Williams has 20; her next opponent, Venus Williams, has seven; fourth-seeded Maria Sharapova has five; and 23rd-seeded Victoria Azarenka has two.
With most of the upsets in the bottom half occurring earlier in the tournament, there were no major surprises on the women’s side on Saturday, aside from Kvitova’s departure, although several other players who have had their best results on grass fell to players not known for their prowess on the surface.
Angelique Kerber, the 10th seed and a semifinalist in 2012, lost in three sets to Garbiñe Muguruza, 7-6 (12), 1-6, 6-2, after holding nine set points in the first set. Sabine Lisicki, the 18th seed and the runner-up here in 2013, lost, 6-3, 6-2, to 15th-seeded, Timea Bacsinszky. Wozniacki won, 6-2, 6-2, over No. 31 Camila Giorgi, who has had her best results on grass. One expected result was that the 21st-seeded Madison Keys, one of four American women left in the tournament, advanced, 6-4, 6-4, over Tatjana Maria of Germany.
The two major contenders in action on the men’s side Saturday both advanced in four sets. Second-seeded Roger Federer opened the day’s play on Centre Court by fending off the big-serving Australian Sam Groth, 6-4, 6-4, 6-7 (5), 6-2. Third-seeded Andy Murray won, 6-2, 6-2, 1-6, 6-1, over 25th-seeded Andreas Seppi of Italy after causing some consternation by calling the trainer out to treat tightness in his right shoulder. Sixth-seeded Tomas Berdych also needed four sets, winning by 4-6, 6-0, 6-3, 7-6(3) over Pablo Andujar.