Rafael Nadal, Novak Djokovic win

ROME -- A week after Novak Djokovic and Rafael Nadal made early exits in Madrid on an experimental blue court, both showed they remain a force on red clay Friday by reaching the Italian Open semifinals.

The top-ranked Djokovic struggled with his serve in the opening set but found his range to eliminate fifth-seeded Jo-Wilfried Tsonga 7-5, 6-1. Nadal defeated seventh-seeded Tomas Berdych 6-4, 7-5.

"In the second set I played one of the best sets on clay this year, and this is encouraging for the challenges to come tomorrow and with Roland Garros," Djokovic said. "I am playing and feeling better every match I play."

Nadal was equally pleased.

"It was a big match and one of the higher quality matches this year because the level of the opponent is high and he plays with big confidence and I played under pressure all the time," he said. "I hit a few fantastic shots, and this kind of shot comes with confidence."

Djokovic, the defending champion, next will play Roger Federer, the winner in Madrid who cruised to a 6-1, 6-2 victory over Italian hope Andreas Seppi. Federer never has won this tournament.

Nadal's semifinal opponent is sixth-seeded David Ferrer, who beat Richard Gasquet 7-6 (4), 6-3.

While Djokovic has not been dominating as he did last year, the Serb still finds a way to win without playing his best. Serving at 5-5 in the first set, he saved a potentially decisive break point with an authoritative serve and volley. Then he took six straight points.

"I really don't compare with 2011," Djokovic said. "This is a new year and I had great results so far in and I'm playing good in Rome so far. I'm increasing the level as the tournament goes on, and this is important."

Down to No. 3 in the world rankings this week, Nadal broke in the opening game to take control of the first set. He recovered a break midway through the second set before pulling ahead for good. Berdych was coming off a runner-up performance at the Madrid Open. He lost to Federer, who then replaced Nadal at No. 2.

Federer never had lost to Seppi, and the 16-time Grand Slam winner took just 19 minutes to win the opening set. Seppi then pleased the partisan crowd by taking the opening game of the second. He had two break points in the next game, but Federer stormed back. The Swiss star closed the match when Seppi failed to return a serve.