Nadal has reached the semi-finals in Dubai for the first time

The British number three battled hard before being swept away in the opening tie-break, and he squandered three break points at 1-1 in the second set.

Nadal managed to hold and then raced through the second set, and he meets Rainer Schuettler next.

Roger Federer beat Robin Vik and faces Mikhail Youzhny in the last four.

Henman's early determination to get to the net almost paid off in Nadal's opening service game.

The Briton came in behind a sliced backhand and steered home a backhand volley to snatch an early chance to break.

I'm frustrated with the outcome, obviously, and somewhat disappointed with my performance Tim Henman

But Nadal, 19, saved the break point, and then two further opportunities, before making Henman pay with a superb backhand winner to claim the fifth game.

Henman saved four break points in the ninth game and was back on level terms after Nadal double-faulted at break point in the next.

The players both held serve to send the set into a tie-break, but then Henman lost his way and lost it 7-1.

And the 31-year-old produced a clutch of errors in the second set allowing Nadal to comfortably ease home 6-1.

"I'm frustrated with the outcome, obviously, and somewhat disappointed with my performance," Henman said.

"But in the context of playing the guy number two in the world it's a good sign that I'm feeling that way about my game.

"I felt fine on the court and my back has been excellent, so it's been a very, very positive week," he said.

Nadal, who has suffered with a foot injury which kept him out of the Australian Open, said: "I had some problems in some games with my serve.

"But I finished the match serving much better and yes, I am pleased with nine aces."

World number one Federer thrashed Vik 6-3 6-2, while Russia's Youzhny reached his first semi-final of the year when he overwhelmed Belgium's Olivier Rochus 6-3 6-1.