Red clay streaked her right leg like a swath of copper-colored paint, the breeze blew the bottom of her skirt askew, her opponent barely blinked in erasing two match points with some audacious shot-making, and the crowd began clapping in rhythmic response to the tension. Turbulence surrounded her in this tiebreaker, but Jamie Hampton stared straight ahead, focused on the finish line.

Playing with guile and grit and cracking some gutsy serves, Hampton swept seventh-seeded Petra Kvitova, 6-1, 7-6 (7), in an impressive performance to reach the fourth round of a Grand Slam for the first time. The 54th-ranked Hampton played smart, tough tennis in defusing the 2012 French Open semifinalist, who could not find the court in the first set and squandered a 4-2 lead in the second. Kvitova's game, as it has done in the past, veered wildly from flashes of brilliance to patches of brutal misses. Hampton won 80 percent of the points played on her first serve; the left-hander won just 53 percent of her first-serve points.

A feisty Hampton, who was 2-7 in her first seven Grand Slam appearances, played with fearlessness in taking a third-set lead over world No. 1 Victoria Azarenka at the Australian Open in January, before a back injury and Vika's improved play stalled her upset hopes. There was no reversal of fortune today. Though hard court is her best surface, Hampton had to feel empowered after defeating another left-handed Czech power player, 25th-seeded Lucie Safarova, 7-6 (5), 3-6, 9-7, in the opening round. Playing with confidence, Hampton had the game plan and the shots to topple Kvitova today, and the agile athlete came out flying.

Whipping her two-handed backhand cross-court to make the taller Kvitova move, Hampton won several points going toe-to-toe with the 2011 Wimbledon champ and defended beautifully when stretched. In the first set, she hit eight winners against just three unforced errors, won nine of 10 points played on her first serve, broke Kvitova in all three of her service games, and ravaged her second serve, winning six of seven points played on her second delivery.

Hampton handled the windy conditions with more concession and care. Kvitova, who is one of the purest ball strikers in the game when she's on rhythm, clanked some cringe-worthy errors as Hampton rolled through the opener in 21 minutes. The scary stat for Kvitova was that Hampton served just 48 percent in the opener; she was so off-target that she was simply playing down the middle at times.

Regaining her range, Kvitova broke and seized a 4-2 second-set lead, but Hampton broke back for 3-4, paying the price for poor shot selection by spraying a slice backhand deep. Hampton, who hit the wide serve on the deuce side with menace all day long, backed up the break with a love hold, then earned two break points in the ninth game. She missed a forehand on the first and badly missed a backhand return down the line off a second serve, though you can't fault her aggression in going after her best shot.

A Hampton ace down the T followed by a fierce "Come on!" sent the second set into a tiebreaker. Neither woman could create separation until Hampton leaned low and blasted a backhand pass up the line for double match point at 6-4. Kvitova hit her best dropper of the match to save it, then drew even when Hampton netted a backhand. A Kvitova forehand winner gave her set point, but Hampton responded by hammering a service winner for 7-7.

When Kvitova nudged a backhand down the line barely wide, Hampton earned her third match point. The American held her ground and drew the 33rd unforced error from her opponent to seal the biggest win of her career; she joins compatriots Serena Williams, Sloane Stephens, and Bethanie Mattek-Sands in the round of 16.