Nadal made it two wins out of two against Murray

Murray had the better of the opening exchanges but missed five early break-point chances and eventually lost the first set 7-5 on a tie-break.

The British number one then broke in the first game of the second set and had further chances to extend his lead.

But Nadal levelled at 4-4 and broke again to seal a thrilling victory.

News conference: Andy Murray

"I had chances and I didn't take them," said Murray.

"It could have gone either way. I'm disappointed to lose but it was a good match, I learned from it.

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"I'm happy that I'm back playing at this level and giving the world number two a great match."

Nadal had said before the match that Murray would be in the world's top six if he had not missed most of the summer with a wrist injury.

Murray produced a performance worthy of that billing, but ultimately Nadal showed the bit extra that takes you to number two in the world.

He staved off five break-points when Murray was dominating early on in the first set and turned up the heat to break as the set reached its climax.

Murray broke back impressively to force a tie-break, but once again Nadal found an edge when it mattered.

The first set was very important, the second set very tough - it was very competitive Rafa Nadal

The first three games of the second set all went against the serve leaving Murray with the advantage.

He held two points for a double break at 4-2 but missed both with backhands that drifted wide.

And from that point on Nadal took over, breaking twice to seal a hard-fought victory.

"The first set was very important, the second set very tough - it was very competitive," said Nadal.

"It was draining physically. I'm happy to have survived and very happy to be in the quarter-finals."

The Spaniard now meets David Nalbandian who beat fellow Argentine Juan Martin del Potro 6-2 6-4 earlier in the day.

Defending champion Roger Federer gained revenge for two defeats earlier in the season as he crushed Argentine Guillermo Canas 6-0 6-3.