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In the aftermath of his opening-round win, Novak Djokovic sarcastically suggested that he might summon martial-arts-master-turned-action-star Chuck Norris for footwork lessons on Madrid's slick, blue-clay courts. When a sprinting Djokovic stumbled and went sprawling across the clay chasing a shot today, he looked like a man in dire need of a stunt double.

The world No. 1 scraped himself off the court, dusted clots of blue clay from the back of his arm, and then took charge of the plot, winning five of the next six games in writing a stubborn Stanislas Wawrinka out of a compelling match script, 7-6 (5), 6-4.

Despite Djokovic's 9-2 record against Wawrinka, this was a tricky test. The world No. 1 passed it by refusing to let a variety of elements—Wawrinka's shot-making skill and tenacity in fighting off the first five set points he faced, the slippery surface that robbed Djokovic of his recovery step at times, and his inability to serve it out on his first attempt—conspire to create a full-blown crisis.

At the outset, Djokovic, who sometimes muttered to himself after losing his balance, countered the uncertain footing by playing with more aggression. He won 16 of his first 18 points on serve, but Wawrinka hung tough, erasing a pair of break points to hold for 2-2. The 10th game was a showcase of Wawrinka's defiance, as he dug out of an 0-40 hole, saving five set points in all to hold for 5-5.

At 5-all in the eventual tiebreaker, Djokovic dipped an imaginative, sharp-angled forehand winner cross-court for the mini-break and earned another set point—the first on his own serve. Striking with conviction, he fired a forehand winner down the line to end the hard-fought, 61-minute opening set. Djokovic jutted his chin out as he strode to his courtside seat, like a boxer who had just taken the challenger's best blows on the chin and was empowered by the experience.

Wawrinka's one-handed backhand is a brilliant swath of a stroke, and he used it in holding for a 1-0 second-set lead. But Djokovic's skill at timing the ball on the rise and his superior speed squeezed the court and coaxed Wawrinka into playing too close to the lines. The defending champion held at love in three consecutive games, winning 22 of 27 points in seizing a 5-2 lead. He stumbled briefly, with Wawrinka saving a match point and breaking in the eighth game; the Swiss then erased another match point to hold for 4-5. But Djokovic drilled three first serves in a row and converted his fourth match point to close in one hour and 45 minutes.

On a day in which Rafael Nadal blew a 5-2 third-set lead to Fernando Verdasco on the same court, Djokovic showed his problem-solving skills and kept his composure to advance to his sixth straight quarterfinal this season, where he will face either good friend Janko Tipsarevic or Frenchman Gilles Simon.