PARIS -- In a foul funk, Petra Kvitova kicked the red dirt on the baseline of the Court No. 1 "Bull Ring," saying bad things to herself in Czech. Her long, 6-foot frame drooped in a more universal language.
The 21-year-old, fighting herself, trailed Jie Zheng 4-3, 15-30 in her second-round match. And then she launched a serve -- thwock! -- at 110 miles an hour, which Zheng couldn't handle. The next one was 113 mph. Kvitova eventually won the game and, having conquered herself, locked down the match.
Like the great, sprawling cafes that dominate the street corners here, the serve is the thing in women's tennis. It's the stroke that matters most, the one that separates the great from the good.
It's why Serena Williams has won 13 Grand Slam singles titles and why Caroline Wozniacki, with 32 weeks at No. 1, has yet to win a major. It's the reason Maria Sharapova and Kvitova, too, have a chance to win here next week at Roland Garros.
It's also why, for the past decade, when the players are under duress, women's tennis is sometimes difficult to watch.
Mary Carillo, whose astute observations have informed the coverage of Tennis Channel this fortnight, was sitting in her shuttle van near Place Vendome earlier this week.
"The currency in women's tennis?" she asked, launching into a laugh before the punch line. "How about holding serve? I've always been a big fan of that concept. It's got to be more than big; it's got to be technically sound, mechanically sound.
"When you get tight, when you're not sound, you are revealed. That's been the biggest problem in women's tennis. Venus Williams comes immediately to mind."
A recent story in Tennis Magazine suggested that mechanics were overrated. Carillo couldn't disagree more.
"If anything," she said, "it's underrated. Technique is also key because bad mechanics cause so many injuries. Classically trained servers tend to have longer, better careers."
Carillo was still talking about mechanics a few hours later during a makeup session in the television compound. In the chair beside her: Martina Navratilova, who knows a few things about serves and -- as a native of Czechoslovakia -- Kvitova, as well.
"Big, strong technique," said Navratilova, a Tennis Channel analyst, "and she really pops it. She's got a good second serve, too."
This is saying something, since Navratilova doesn't like anybody's second serve. Indeed, on Thursday, Kvitova's second serves were sometimes faster than Zheng's first serves.
In the NFL, length has come be a prized asset. Length and long limbs equal leverage. Studies say that tall people are generally more successful in life than short people. This seems to be true in sports, as well, whether it's a defensive end trying to turn the corner on a 330-pound offensive tackle, or a tennis player trying to hit the 283.5 square feet of the service box. A simple matter of geometry.
Remember Juan Martin del Potro's sweet U.S. Open run a few years ago? It was like the 6-6 Argentine, a human pendulum, was hurling slingshots across the net. It is much the same with Kvitova, except she has the advantage of being left-handed (the only one in the top 30), which creates unfamiliar angles.
"Lefty-ness really helps," ESPN analyst Pam Shriver said. "You put that player in the mirror, turn them around, and they're not the same. Kvitova's length really helps her not only hit with force but also in getting to balls and applying spin."
Kvitova first crossed into the consciousness of the casual tennis fan a year ago at Wimbledon.
She entered play at the All England Club ranked No. 62 in the world with a career record of 0-4 on grass. Yet, Kvitova ripped through the draw, beating Victoria Azarenka and Caroline Wozniacki on her way to the semifinals. She lost credibly to Serena Williams, but her ranking vaulted to No. 30. It might have been too much too soon. Kvitova lost her next five matches and finished the season losing 10 of 15 matches.
In 2011, Kvitova has gathered herself and, despite a series of injuries (abdominal muscle, back, hip), has progressed nicely. She's won tournaments in Brisbane, Paris and, most recently, Madrid. That impressive win on clay, with victories over Vera Zvonareva and Azarenka, has pushed her all the way into the top 10, at No. 9. She is a complete player with a thumping forehand and a backhand that's even better.
Kvitova is exceedingly shy, at least around the media. After her first-round win over Greta Arn, the entire postmatch interview consisted of three questions and three brief, halting answers, featuring four "I don't knows."
She hasn't forgotten where she comes from, though. After her victory in Madrid, most elite WTA players played in Rome. Kvitova opted instead to play a minor ITF event in Prague out of loyalty to the people who had helped her train since juniors.
On Saturday, the towering Kvitova plays diminutive American Vania King in the third round. Kvitova had 7½ inches on Jie Zheng and now she'll have a seven-inch advantage over King.
The 5-5 American will have to go to great lengths to beat her.
Greg Garber is a senior writer for ESPN.com.