Nadal dominated the match from the first set[Reuters]

Defending champion Rafa Nadal routed former winner Andy Roddick 6-2 6-1 6-3 on Friday to reach the semi-finals of the US Open.

Nadal, the only men's player yet to lose a set in the tournament, set the tone early by breaking the American in his first two service games to race to a 4-0 lead and going on to break Roddick six times in all in the one-hour 53-minute romp.

The second-seeded Spaniard advanced to a last-four clash with fourth-seeded Andy Murray of Britain, a 7-5 6-4 3-6 7-6 winner against American John Isner.

Saturday's other men's semi-final will pit top-seeded world number one Novak Djokovic of Serbia against 16-time grand slam winner Roger Federer, who owns five U.S. Open titles.

Roddick, who was overwhelmed by the Spaniard's pounding, pinpoint groundstrokes, looked sluggish and twice received leg rubdowns from the trainer during the match.

"Andy had a really tough match yesterday and probably he was tired," Nadal told the Arthur Ashe Stadium crowd, referring to 2003 winner Roddick's four-set win against fifth seed David Ferrer of Spain.

"I am sorry for him."

But Nadal, 25, showed no mercy on the court.

The 10-time grand slam winner powered 35 winners past the hapless Roddick including 22 forehand winners.

The American managed only one backhand winner and none from the forehand side in the match.

The Spaniard then turned his eye toward the semi-finals.

"It's always a pleasure to play against Andy (Murray). He is probably one of the players with more talent on the tour,"said Nadal.

"The matches against him are always exciting, so it will be a big challenge for me."

Nadal defeated Murray in this year's semi-finals at the French Open and Wimbledon. Murray beat Nadal in the US Open semi-finals in 2008 before falling to Federer in the final.

"Tomorrow I have to play aggressive, I have to play my best tennis if I am going to have any chance," said Nadal.

Source: Agencies