KEY BISCAYNE, Fla. -- The frisky, funky, hip-swinging celebration dance has surfaced before, most notably at last year's U.S. Open, where it was seen for the first time.
The Petko Dance, which has its origins in a bet with her coach, happened again after Andrea Petkovic authored a career win over Maria Sharapova in the fourth round of this year's Australian Open. But it had never been executed after a takedown of the world's No. 1-ranked player. Until Monday, that is.
Petkovic, a rising 23-year-old German with a thoughtful but forceful game, completely unstrung Caroline Wozniacki in the fourth round of the Sony Ericsson Open, 7-5, 3-6, 6-3. The match went 2 hours, 24 minutes in the sultry heat of south Florida.
"Nothing was going on with my forehand, nothing was going on with my backhand," said an uncharacteristically terse Wozniacki. "I lost the match."
Wozniacki used that robotic phrase, or one like it, five more times. But make no mistake: This was not a fluke.
Petkovic never stopped slashing her groundstrokes -- a penetrating backhand and a lethal forehand -- and disrespecting Wozniacki's serve. Petkovic, despite 45 unforced errors, broke Wozniacki five times. The Dane, who prides herself on defense and mistake-free tennis, had a relatively staggering 41 unforced errors.
Petkovic said her strategy was to mix things up against Wozniacki.
"Most of the players think they can overpower Caroline," Petkovic explained. "I think that's the wrong approach, because that's where she's most comfortable, when she can run and bring most balls back. If you try to hit every single shot with full power, she just gets more comfortable and eventually you're going to miss. She's not going to miss the last one.
"What I tried to do: Just be patient and wait for the short ball."
It was the first time a German woman has beaten the No. 1 player in a completed match since someone named Graf beat Martina Hingis in the 1999 final at Roland Garros.
"Oh," said Petkovic, who practiced with Steffi Graf a few weeks ago in Las Vegas, "I didn't know it. I get the questions actually every time from the German reporters about Steffi. I managed to be in the quarters [in Melbourne], which is good for me. But it's not nearly close to winning 22 Grand Slam titles. So just being in one sentence [with Graf] for me, is a great honor."
Petkovic's triumph, while not breaking news in the United States, made an impression elsewhere. Just after the match, Petkovic was listed among the top 10 current subjects according to Twitter's worldwide trends.
The funny thing? She's even better off the court. Petkovic is probably the best interview among the WTA's many players, comparable to Andy Roddick on the men's side, a quirky, honest personality with a ton of energy. She admits this gets her in trouble all the time.
Petkovic speaks four languages and is working on a fifth. She drove to last year's tournament in Hertogenbosch, The Netherlands. Her style and command of English alone led to a position as ESPN.com's resident blogger at last year's U.S. Open. Her posts, featuring some disturbing interior monologues, were well received.
On Sunday, as she walked to a scheduled autograph session, she knowledgeably discussed the differences between NBA and NCAA players. She observed that the NBA bench players, even after a spectacular dunk by, say Blake Griffin, sit lethargically, looking bored. When a player makes a terrific shot in the tournament, his bench goes crazy. Petkovic, walking in the heavy evening foot traffic of Sony Ericsson fans, broke out into a reasonable re-creation of such a moment; her vertical leap, alone, was impressive.
Petkovic is a relatively late bloomer, since she attended 13 years of school in Germany before fully committing to tennis. She truly seems to enjoy the big moments. In her only previous encounter with a No. 1 player, she stretched Serena Williams to three sets last year in Rome.
"I was always mentally tough in the juniors," Petkovic said. "I love the close moments. I love when it's 4-all in the third, even if I sometimes lose it in the end or mess it up. Afterward, I always feel the most alive in those moments."
Petkovic, currently ranked No. 23, could be a career-high No. 20 when the rankings come out next week.
Wozniacki, who won the BNP Paribas Open last week at Indian Wells, looked tired during the match and afterward as well.
"I have played a lot of matches," she said, "but I have been doing so well. Today, I took the wrong decisions at the important moments. That's what happens sometimes. I'm not going to dig a hole for myself or dig a grave. I'm just going to take a few days of rest now, maybe on the beach, get some of the tan lines off."
There's no place better than South Beach to soak up some rays and forget the past. Petkovic, meanwhile, is into the quarterfinals, where she'll play Jelena Jankovic, who happens to be a good friend.
The secret of Petkovic's success may be that she is actually a stealth Serbian -- by birth. She was born in Bosnia, but raised almost entirely in Germany, where her father played professional tennis and coached after the war heated up. She grew up playing with the Serbs in juniors and feels a close connection to them. She, Ana Ivanovic and Novak Djokovic were all born in the same year, 1987.
Ivanovic and Petkovic are playing doubles together here and have side bets -- $5 for an ace or a set-ending shot, $3 for a particularly good volley -- and Petkovic happily told the media that they pay each other during changeovers.
"Because otherwise, you can sneak out and then it's gone, the money," Petkovic said, causing the attending WTA communications official to visibly grimace.
The biggest news to come out of Petkovic's marathon news conference -- her transcript ran more than four pages -- was that, going forward, the Petko Dance has run its course. After Miami, Petkovic said, it will never be seen again.
"I'll try and do it as much as I can here, because then it's gone," Petkovic said. I'm a little sad. It was a nice phase and it was nice fun, but now I'm getting a little tired of it. Time to move on.
"Any inspirations, I'm always open. If somebody has a new thing, you can send it to my email address."
And as she launched into that address -- can you picture Serena Williams or Maria Sharapova spelling out her email address in a public setting? -- the WTA communications manager grimaced again.
Greg Garber is a senior writer for ESPN.com.