New York, Sep 10 (IANS): Defending champion Rafael Nadal crushed Andy Roddick in the quarterfinals of the US Open here Friday to set up a semifinal clash against World No. 4 Andy Murray.

Muuray eliminated American John Isner in another quarterfinal.

With top seed Novak Djokovic and third seed Roger Federer already into the last four, it will be for the second time this year the top four seeds in the men's singles have advanced to the semifinals of a Grand Slam. The first time was at the French Open.

"It seems like top four players are doing well," Nadal was quoted as saying by Xinhua.

"For last few years top four players are very solid in almost every tournament. That was difficult to to see that in the past because it is very difficult to achieve that. Tennis is a very competitive sport, so I think is very good news for the sport."

The second-seed Nadal met little resistance from the top American player as the Spaniard converted six of seven break points to beat the 2003 Champion Roddick 6-2, 6-1, 6-3 in 1 hour, 53 minutes.

Top-seed Novak Djokovic meets third-seeded Roger Federer in the first semifinal Saturday followed by the Nadal-Murray contest.

Djokovic enjoys a 62-2 record including nine titles in 2011. His first loss this season came when Federer beat him in a thrilling French Open semifinal.

His second came in the Cincinnati Masters final as the Serb retired after trailing 4-6, 0-3 against Murray.

In the Nadal-Roddick match, the American never broke his opponent and committed 25 unforced errors, 12 more than the Spaniard. The 25-year-old Nadal played more aggressive, hitting 35 winners and overwhelming Roddick's 15.

Roddick received medical treatment on his left thigh twice during the match but when Nadal broke Roddick's serve in the very first game it was an indication that Roddick had no weapons to hurt Nadal, who made the semifinals at the Open for the fourth straight year.

In an earlier match, Murray dealt with No. 28 Isner's big serve and used a variety of lobs and pinpoint passing shots to win 7-5, 6-4, 3-6, 7-6 (2).

For the third straight major, Nadal and Murray will play each other in the semifinals. Nadal beat Murray in straight sets at the French Open and in four sets at Wimbledon.

Murray, one of tennis' top returners, weathered 17 aces at up to 140 mph from the 6-foot-9 Isner but repeatedly got back serves topping 130 mph and managed to break the American twice in a row bridging the first two sets.

"It is so frustrating playing against him because you feel like you are playing good tennis, and it is so hard to break him," Murray said.

While Murray is a three-time Grand Slam runner-up, Isner was playing in his first quarterfinal at a Grand Slam.

Murray's past Grand Slam final appearances include losses to Djokovic at the Australian Open in January and to Federer here in 2008. He is seeking to become the first British man to win a Grand Slam title since 1936.

Murray is now only the seventh man in the Open era to reach at least the semifinals at all four Grand Slam tournaments in a single season. Three of the others are Federer, Nadal and Djokovic.