LONDON -- For 34 matches over 4½ 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.

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.

Late Monday afternoon, British bookmakers were making Lisicki the favorite to win a trophy that hours earlier seemed destined for Williams. Asked whether that affects her in any way, Lisicki shot back: "No, not at all." Not even a little bit? Lisicki didn't blink and answered, "No."

It was the same steely demeanor the quick-with-a-smile Lisicki displayed at key moments on court, weathering a near-collapse in which Williams grabbed nine consecutive games to take the second set and go up 3-0 in the third.

"I just was fighting for every single point," Lisicki said, "no matter what was happening out there."

Williams hadn't lost a match anywhere since her three-set defeat against Azarenka in the final of the Qatar Open on Feb. 17. She hadn't even lost a set since the French Open quarterfinals against Svetlana Kuznetsova on June 4. But Lisicki showed things would be different Monday with an early five-game run, including when she smacked a forehand return winner to break at love and take the opening set.

Williams was asked whether the pressure to win got to her.

"Not at all," she said. "I mean, every time I step out on the court, I'm the favorite."

That sort of thing hasn't mattered one bit at this Wimbledon.

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