Nadal has twice been taken to three sets so far in Dubai

The defending champion appeared to be cruising when he had triple break point on Andreev with the score at 6-2 3-3.

But the Russian fought back to win the set and break Nadal early in the third, forcing the Spaniard to dig deep and finally edge through 6-2 3-6 7-6 (7-2).

He will be joined in the last eight by world number one Roger Federer, who beat Italy's Daniele Bracciali 7-5 6-3.

It was a bit of a struggle in the beginning but it's not easy to get the breaks here it seems Roger Federer

The Swiss right hander saved break points in the third and fifth games of the first set before crucially breaking in game 12.

He then raced to a 3-0 lead in the second, but wasted eight break points in game four before sealing victory and a match with fifth seed Novak Djorkovic of Serbia, who beat German Rainer Schuettler 7-6 (7-5) 6-3.

"It was a bit of a struggle in the beginning but it's not easy to get the breaks here it seems," said Federer.

"He was serving really well and it came down to 10 minutes for me really, the end of the first, beginning of the second. That made a difference and I could run away with it."

Nadal, like Federer, is playing in his first tournament since the Australian Open last month and was also taken to three sets in the first round by Marcos Baghdatis.

Winning the third set in a tie-break was very important. I have had two good tough matches now after the month-long break Rafael Nadal

And the Spanish 20-year-old said: "Igor is a very tough opponent. I lost to him two years ago on clay in Valencia, so I knew I needed to play a very good match to beat him.

"Winning the third set in a tie-break was very important for my confidence. I have had two good tough matches now after the month-long break."

Russian third seed Nikolay Davydenko will not be in the last eight, though, after he crashed out in three sets, losing to Belgian Olivier Rochus 4-6 6-4 6-2.

Mikhail Youzhny of Russia also upset the form book by overcoming sixth-seeded Czech Tomas Berdych 7-6 (8-6) 6-3.