Del Potro cruises, Verdasco woe

Juan Martin Del Potro remains unbeaten on clay in 2012 following an easy victory over Alexandr Dolgopolov in the Madrid Open quarter-finals.

The Argentine, a winner in Estoril last week, made it 10 wins out of 10 on the surface with a 6-3 6-4 triumph on Friday. He has yet to drop a single set on clay this season.

Del Potro needed just 84 minutes to reach the last four, breaking his opponent's serve three times in total.

Dolgopolov's 'mix it up' game had been tipped in some quarters to cause problems but in the end it was Del Potro's power play which prevailed on the slick blue clay.

Fernando Verdasco, meanwhile, came back down to earth with a bump.

Less than 24 hours after his shock win over Rafael Nadal, Verdasco was thrashed 6-1 6-2 by Tomas Berdych.

The Spaniard had taken more than three hours to upset Nadal on Thursday, posting his first win over his compatriot in 14 attempts, and he cut a weary figure against Berdych's powerful strokes.

Berdych, who lost just two games in dispatching Gael Monfils in his previous match, gained control early on control and refused to relent as he eased to victory.

The Czech lost just nine points on serve in the match and has yet to lose his delivery in three outings so far on the Caja Magica's blue clay.

Berdych will face Del Potro on Saturday for a place in the final.