Blake loses in quarterfinals of Rome Masters

Updated: May 9, 2008, 10:03 AM EST Comment

"It's my first Masters Series semifinal, so I'm very pleased," Wawrinka said.

Blake was coming off three-setters in his opening two matches, and the American appeared to lose energy as the match wore on.

Blake missed an easy volley to hand Wawrinka a break in the first game of the third set, and Wawrinka rolled from there.

Wawrinka called for a trainer to treat his lower back with a 6-5 lead in the second set, then again with a 2-1 lead in the third, but the problem did not appear to affect his play.

Wawrinka is ranked a career-high 24th this week after reaching the semifinals of the Barcelona Open last weekend, losing to David Ferrer.

His next opponent will be either Andy Roddick or Tommy Robredo, who were playing later.

Wawrinka said his back problem stemmed from the many matches he's played lately.

"I will try to be 100 percent for tomorrow," he said.

Roddick holds a 7-0 career record against Robredo.

Top-ranked Roger Federer was next up on center court against Radek Stepanek of the Czech Republic.

The night match featured Australian Open winner Novak Djokovic against Spanish clay-court specialist Nicolas Almagro.

The Rome Masters is a clay-court tuneup for the French Open, which begins May 25.