RODDICK INJURED

Andy Roddick retired with an injury in the first set Wednesday, allowing Andy Murray to advance to the semifinals of the Ericsson Open.

Roddick took a medical timeout at 4-3 and left the court, then played six more points. On the final rally, he hit a half-volley at the net, and when Murray pulled a backhand crosscourt for a winner, Roddick didn't try for the ball.

Roddick then conceded by shaking hands with Murray. The injury leaves in doubt Roddick's availability for the U.S. Davis Cup team's match against Spain on April 6-8.

Despite the injury, Roddick remains hopeful of playing for the US in next week's Davis Cup tie against Spain.

"That's obviously playing a part in this process. I'm just kind of concerned about that," he said

"I think the medical term for the injury is 'the bottom of my ass hurts,'" he added.

"He hit a volley behind me and I kind of lunged at it and jarred something. More and more it started becoming like a sharp pain and then I started feeling it even when I was just kind of cruising around the court, not even in points.

"It wasn't getting better. It was getting worse, which isn't a good sign."

Murray became the first Brit to reach the Key Biscayne semifinals since Tim Henman in 1998. The Scotsman is ranked a career-high 12th and leads the men's tour with 23 wins – two against Roddick – in 27 matches.

Murray's opponent Friday will be the winner of the match Wednesday night between second-seeded Rafael Nadal and No. 10 Novak Djokovic.

No. 14 Shahar Peer advanced to the women's semifinals, winning the first nine games and beating No. 24 Tathiana Garbin 6-0, 6-3.

Peer's opponent Thursday will be the winner of the match Wednesday night between three-time champion Serena Williams and No. 8-seeded Nicole Vaidisova. Peer nearly pulled off an upset against Williams in the quarterfinals of the Australian Open in January, losing the third set 8-6.

Peer, a 19-year-old corporal in the Israeli Army, has a 20-6 record this year and is ranked 16th. She won 31 of 55 points on Garbin's serve and broke five times.

The other women's semifinal Thursday will be between top-ranked Justine Henin and Anna Chakvetadze. With second-ranked Maria Sharapova's loss Wednesday to Williams, Henin is assured of remaining No. 1 next week.