Madrid, Spain (Sports Network) - Janko Tipsarevic stunned world No. 1 Novak Djokovic in an all-Serbian quarterfinal showdown Friday at the $4 million Madrid Open, an ATP World Tour 1000 Masters event.

The seventh-seeded Tipsarevic upended the defending Madrid champion Djokovic in straight sets, 7-6 (7-2), 6-3, in 1 hour, 43 minutes on the blue clay at Madrid's Magic Box. Tipsarevic posted the only break of the match in the second set en route to the upset.

Djokovic went 0-for-7 on his break-point chances in the setback.

Tipsarevic is now 2-4 lifetime against his good friend and fellow Belgrade native. Djokovic bested "Tipsy" in a quarterfinal in Dubai two months ago.

The reigning Australian Open, U.S. Open and Wimbledon champion Djokovic beat two-time winner Rafael Nadal in last year's marquee Madrid finale.

Meanwhile on Day 6, sixth-seeded Czech slugger Tomas Berdych drilled sluggish 15th-seeded Spanish crowd favorite Fernando Verdasco 6-1, 6-2 and surging Argentine Juan Martin del Potro, seeded 10th, dismissed 16th-seeded Ukrainian Alexandr Dolgopolov 6-3, 6-4. Verdasco stunned the great Nadal in three sets on Thursday, including overcoming a 2-5 deficit in the third set.

The former Wimbledon runner-up Berdych and former U.S. Open champion del Potro will square off on Saturday. "Delpo" is fresh off his clay-court title in Estoril last week.

The 2012 Madrid titlist will earn $770,000.

The Sports Network