-- Maybe this was the equivalent of a market correction for women's tennis.
Perhaps Simona Halep's stunning 6-0, 6-2 victory over No. 1-ranked Serena Williams on Wednesday mirrored the blindside stock slide of 2008.
No one, probably Halep included, saw this coming.
Williams came in with a 50-4 record against the other seven participants in the BNP Paribas WTA Finals in Singapore and had won 16 consecutive matches in the year-end event. Halep was 0-for-8 against top-three players and 0-for-4 against the No. 1.
And then Halep handed Serena her worst loss in more than 16 years -- half a life ago for the 33-year-old. It was only the second main draw match in which Serena won two or fewer games.
"Yeah," the 18-time Grand Slam singles champion said afterward, "embarrassing I think describes the way I played. Very embarrassing."
It was over in a scant 65 minutes and the 23-year-old Romanian called it the best match of her life, and the second-most important, after her appearance in this year's French Open final.
"I have no words to explain how I feel," Halep said in her postmatch news conference. "It was an amazing match for me. I was aggressive, and after first set I wasn't scary."
Oh, she was scary all right. Halep actually won the first eight games of the match. Overall, she served phenomenally well, winning 65 percent of her first-serve points and a remarkable 68 percent (13 of 19) of her second serves.
Most important, Halep converted five of her six break-point opportunities. Serena was 0-for-6. That first-set bagel was the first for Serena in six years, when older sister Venus did it in the 2008 edition of this tournament. That, in fact, was the last time Serena lost a match at the year-end event.
Williams' serve -- widely viewed as the best in the history of women's tennis -- was anemic. She double-faulted seven times and won fewer than half her first serves. In the first set alone, there were six double faults and, for the match, 36 unforced errors.
"My forehand was off today again," Williams said. "I guess it went on an early vacation.
"Lord knows my serve was as well. My serve was, at best, in the 10-and-under division in juniors."
Halep, the No. 4-ranked player, is now 2-0 in round-robin play and has a terrific chance to reach the Saturday semifinals of this tournament. She'll play Ana Ivanovic on Friday.
Serena, the two-time defending champion, is 1-1 and probably needs to beat Eugenie Bouchard on Thursday to reach the Red Group semifinals.
In the Red Group's second match, Ivanovic (1-1) defeated Bouchard (0-2) by the score of 6-1, 6-3.
On Thursday, the White Group plays its second round-robin matches. Agnieszka Radwanska (1-0) meets Caroline Wozniacki (1-0) and it's Maria Sharapova (0-1) versus Petra Kvitova (0-1). Serena's loss means that Sharapova technically still has a chance to finish as the year-end No. 1.
Those matches can be seen on WatchESPN, beginning at 1:30 a.m. ET.
Halep, after beating Bouchard in her first match, has now dropped only seven games in four sets. She had never beaten Serena in three previous matches but said she was surprised by how calm she was.
"She's the best player in the world," Halep said. "I have nothing to lose, just to play. After this match, I learned many things. I learned that I have to believe in my chance and just go on the court and play my game."
Not bad for a debut at the WTA Finals.
Seventeen months ago, Halep was ranked No. 64 in the world. Since then, she has raised her ranking 60 spots, won eight titles, reached a major final and now beaten the No. 1 player.
"Personally, I've never seen her play like this," said Williams, who came into the tournament nursing a sore knee. "Ever. But, hey, you've got to step up to the plate. She did and I didn't."
For Halep, who has struggled with injuries (toe, back, abdominal), this might have been a game-changer. "Everything," she said, "is possible."