ROME — Andy Roddick and Radek Stepanek retired from semifinal matches at the Rome Masters today, setting up a final between Stanislas Wawrinka and Novak Djokovic.

Roddick pulled out with a back problem after falling behind 3-0 in the first set against Wawrinka.

"I felt a little something last night in my back when I was getting treatment. Then, one wrong movement and I had a complete spasm," Roddick said. "I can't really move my left arm right now. You can't really play around that."

Stepanek stopped while trailing Djokovic 6-0, 1-0 with an apparent wrist injury and also looked affected by the heat. Stepanek called for a trainer after the first set, then retired one game later.

On Friday, Stepanek eliminated top-ranked Roger Federer in this clay-court tuneup for the French Open.

Roddick pulled up awkwardly after Wawrinka hit a forehand winner in the third game, then asked for a trainer on the changeover. He came back out and double-faulted, then quit.

"I warmed up OK, but then just one movement triggered it," Roddick said. "I can feel it even when I take a deep breath now."

Wawrinka reached his second final of the year. He is ranked a career-high 24th this week after reaching the semifinals of the Barcelona Open last weekend, and will move into the top 10 next week.

The Hamburg Masters begins Monday, and Roddick isn't sure how his back will react.

"My plan is to get this thing better," he said. "I probably won't be able to hit the next couple of days."