LONDON (AP) ― For 34 matches over 4 1/2 months, on hard, clay or grass courts, Serena Williams was unbeaten ― and, in the minds of many, unbeatable.

So it was apt, somehow, that the longest winning streak in women’s tennis since 2000 would end at this memorably unpredictable edition of Wimbledon, where up is down, where seedings and pedigree mean nothing whatsoever, where even five-time champion Williams looked lost at the start and, most surprisingly of all, the finish of her fourth-round match.

Stumbling on the Centre Court grass a couple of times while her game slumped in crunch time, the No. 1-ranked and No. 1-seeded Williams dropped the last four games to bow out 6-2, 1-6, 6-4 Monday against 23rd-seeded Sabine Lisicki of Germany.

“Didn’t play the big points good enough,” said Williams, who had won three of the past four Grand Slam titles, including Wimbledon a year ago and the French Open less than a month ago. “I didn’t do what I do best.”

Oddly passive down the stretch, Williams essentially let Lisicki to do what she does best: dictate points quickly with a big serve, powerful returns and pinpoint groundstrokes. If that sounds familiar, could be because it’s the formula Williams uses to dominate her sport. Except on this breezy afternoon, Lisicki compiled a 10-7 edge in aces, a 35-25 lead in winners, and broke Williams five times.

“Come on, guys, let’s get with it. She’s excellent,” a composed Williams said at her news conference after blowing leads of 3-0 and 4-2 in the third set. “She’s not a pushover.”

Especially at Wimbledon. Her game is built for grass. Lisicki is a mediocre 16-15 at the other three Grand Slam tournaments and 17-4 at the All England Club. She reached the semifinals at Wimbledon in 2011, and is into her fourth quarterfinal, coincidentally beating the reigning French Open champion every time: Svetlana Kuznetsova in 2009, Li Na in 2011, Maria Sharapova in 2012, and Williams in 2013.

“Good omen,” Lisicki said.

“Obviously,” she said, “I went into the match feeling that I could win.”

Might have been the only person who felt that way. After all, Williams owns 16 major championships, and entering Monday, the 31-year-old American had won 46 of 48 matches this season, and 77 of 80 since the start of Wimbledon in 2012.

“You cannot be perfect, every match, all year,” said Patrick Mouratoglou, the French coach who began working with Williams last year. “She won 34 matches in a row. It has to stop one day. It has to happen. And it happened today.”

The inevitability of failure, even for the most successful player, has never been made clearer than during this tournament. This was only the first day of the fortnight’s second week, yet Williams joined quite a list of those already gone: Roger Federer, Rafael Nadal, Victoria Azarenka and Sharapova ― all major title winners, all former No. 1s, all out by the end of Day 3.

“This,” summed up 17th-seeded Sloane Stephens, “has been a crazy Wimbledon.”

Sure has. No U.S. men reached the third round, something that last happened 101 years ago, and Williams’ departure made Stephens the lone American singles player left. The 20-year-old Stephens’ first quarterfinal at the All England Club comes Tuesday against No. 15 Marion Bartoli of France, the 2007 runner-up.

The other matchup on their half of the draw is No. 8 Petra Kvitova of the Czech Republic, the 2011 Wimbledon champion, against No. 20 Kirsten Flipkens of Belgium. Tuesday’s remaining quarterfinals are No. 4 Agnieszka Radwanska of Poland, who lost to Williams in last year’s final, against No. 6 Li of China; and Lisicki against 46th-ranked Kaia Kanepi of Estonia.

Kanepi reached her fifth Grand Slam quarterfinal, and second at Wimbledon, with a 7-6 (6), 7-5 victory over 19-year-old Laura Robson, the first British woman in the fourth round at the All England Club since 1998. Robson, like others, took note of Monday’s most significant outcome.

“I thought for sure Serena was going to win the tournament,” Robson said, expressing a popular sentiment.

On Wednesday, the men’s quarterfinals on the draw’s top half are No. 1 Novak Djokovic of Serbia, a six-time Grand Slam titlist and the only remaining past Wimbledon winner, against No. 7 Tomas Berdych of the Czech Republic, the 2010 runner-up; and No. 4 David Ferrer of Spain against No. 8 Juan Martin del Potro of Argentina, the 2009 U.S. Open champion.