WIMBLEDON, England -- Just when tennis aficionados were savoring the prospect of a Venus Williams-Kim Clijsters semifinal, a 22-year-old Bulgarian ranked No. 82 in the world and a confidence-challenged Russian, who previously had never beaten her opponent, had their own agendas.
Rated by oddsmakers before the match as a 150-to-1 shot to win the title, Tsvetana Pironkova throttled Williams, the five-time Wimbledon champion, 6-2, 6-3 in a scant 1 hour, 25 minutes. It was easily the most surprising result of an enlightening fortnight -- Andy Roddick's loss to Yen-Hsun Lu notwithstanding. Vera Zvonareva, meanwhile, surprised Clijsters 3-6, 6-4, 6-2.
Tennis has a wonderful way of bringing history alive, and on Tuesday Pironkova and Williams met for the first time since the Bulgarian defeated Venus at the 2006 Australian Open. Many here, after a quick study of the quarterfinals matchups, had conceded a third consecutive finals berth for Venus opposite her sister Serena, but Pironkova, 22, did not get that memo.
The final point nicely framed where these two players are in their careers:
Williams, charging to the end, had already saved two match points in an earlier service game. Pironkova, serving like vintage Williams, hit two big offerings to create two more match points. Williams hit the approach shot you have seen hundreds of times and loped to the net in three or four strides. Surely, as she made the familiar stretch to her right for the forehand volley, she would save this third match point. But Williams was a half-step late, her racket just a tad soft, and the ball caromed wide.
Pironkova fell to her back at the baseline and the crowd at Court No. 1 rose to its feet. It was the 13th Grand Slam singles victory for Pironkova, who becomes the first Bulgarian to reach a Grand Slam semifinal in the Open era. Williams was going for her landmark 200th major win.
"I just didn't get enough balls in today," Williams observed later. "I just let it spiral and didn't get any balls in. I mean, I had a lot of opportunities and a lot of short balls. I just seemed to hit each one out.
"Obviously, she's played well to get this far, but I don't think I did anything right today. If I hadn't contributed to her effort, I'm not sure that it would have gone as well."
Pironkova -- who had won only one career match on these lush lawns heading into this year's tournament -- continues her greatest Grand Slam singles run.
But it wasn't the first time she beat Williams.
Pironkova was an 18-year-old unknown from Bulgaria when she made headlines around the world four years ago. She stunned Williams in a memorable opening match Down Under, 2-6, 6-0, 9-7. Going back to 2002, Williams has played in 32 Grand Slam singles events, and it remains the only time in that span she lost in the first round.
Pironkova's very first WTA-level main-draw match came the year before, against Williams in Istanbul. Pironkova won all of four games.
Williams, who turned 30 less than two weeks ago, looked very much her age.
"I missed all shots today: forehand, volley, backhand," Williams said. "If there was a shot to miss, I think I missed it. I'm not pleased with this result, but I have to move on. What else can I do? Unless I have a time machine, which I don't."
Looking for a little context? This was Williams' 77th match at Wimbledon -- and her worst loss, in terms of games won.
Afterward, Pironkova said it felt like a dream, but when asked if she was surprised, her eyes narrowed.
"I think I played pretty well today," she said in deliberate English. "I have one win over her and I actually thought I could win, and I went for it."
For Zvonareva, it represented a triumph over herself. The 25-year-old Russian has always had the shots to succeed at the highest level, but she has been her worst enemy. On Tuesday, it was Zvonareva who was focused and forceful in the important moments; Clijsters, who had beaten Zvonareva in their five previous matches, was uncharacteristically erratic.
Zvonareva explained her newfound composure this way: "I think it comes with experience. You grow up. You're more mature. You know you've been in different situations and you know how to manage them better. I think right now I have learned a lot from the past."
Clijsters stroked 36 unforced errors, which, along with Zvonareva's more efficient service game, turned the match.
Clijsters credited Zvonareva with staying on top of her, particularly with a hard-to-read backhand, but it should be remembered that the Belgian missed Roland Garros this year with a foot injury.
"It was disappointing to come from, you know, five, six weeks off without hitting one ball," Clijsters said. "That was probably also not a great preparation. But I'm not blaming that at all."
Although Pironkova beat Williams decisively, she had some help. Like Clijsters, Williams sprayed the ball around, committing 29 unforced errors -- compared to just six for Pironkova. And like Clijsters, Williams served poorly, winning only 58 percent of her first-serve points and 47 percent of her second serves.
There are no grass courts in Bulgaria, and when Pironkova first tried to qualify here on grass, she thought, "Wow, it's impossible. How can I play on this surface?"
Clearly, she has mastered the slippery slope that is grass -- to the extent that this result did not surprise her.
"I cannot say what surprised me," she said. "But I think it was quicker than I thought. I expected, like, a longer match."
Now, after near-simultaneous upsets, two surprise semifinalists face off on Thursday. One of them will find herself in a career-first Grand Slam final on Saturday.
Greg Garber is a senior writer for ESPN.com.