World number two Rafa Nadal scraped into the quarter-finals of the Cincinnati Open after beating fellow Spaniard Fernando Verdasco 7-6 6-7 7-6 in a fierce battle yesterday but his rivals all had comfortable paths into the last eight.

Seven of the top eight seeds have reached the quarter-finals with world number one Novak Djokovic and rivals Roger Federer and Andy Murray having little trouble.

The all-Spanish contest though was a grueling grind in the mid-day heat that lasted three hours and 38 minutes and was decided by a mistake-filled third tie-break.

It was just the fifth time in 635 matches that Nadal has played in a three tie-break game but he has won on all five occasions.

Nadal, who gave up three match points in the decisive tie-break, stuck with the task to finish off a determined Verdasco despite never finding his rhythm.

While it was as close as could be, the game lacked the expected quality as Nadal made 41 unforced errors and Verdasco 59 while the world number two managed only 24 winners.

"Probably I had a little bit fewer mistakes than him when the match was close. It's true he was playing more spectacular points than my ones but I think I played with less mistake than him at the end," said Nadal.

Nadal will face Mardy Fish in the quarter-finals after the American beat France's Richard Gasquet 7-5 7-5 .

World number one Djokovic took his season record to 55-1 with a straightforward 6-3 6-3 win over Czech Radek Stepanek.

Djokovic showed some signs of weariness and conceded that it was a game he needed to push himself through.

"There are days like this where you don't feel like playing. But I hate losing, so I need to win and that is what motivates me on the court," he said.

Britain's Andy Murray had a relatively comfortable 6-2 7-5 win over American qualifier Alex Bogomolov.

The win gave Murray revenge for his poor defeat to Bogomolov in Miami earlier this year.

"I played better today. I was struggling a lot in Miami and didn't play well at all. So I am glad to come through in two sets and forget about the match I played against him in Miami," he said.

Murray will now play Frenchman Gilles Simon, who produced the only real surprise of the day when he beat fifth-seed Spaniard David Ferrer 6-4 6-7 6-4.

Switzerland's Federer, looking relaxed and composed, took just 55 minutes to defeat American James Blake 6-4 6-1 and he will now meet Czech Tomas Berdych who easily dealt with Spain's Nicolas Almagro 6-2 6-2.

"He's a dangerous player," Federer said of Berdych who beat him twice last year, including at Wimbledon.

"He hits the ball extremely hard and he can go through matches and dominate from the baseline.

"I have to make sure I get into his service games and play aggressively myself and see where it takes us.

"We've had some tough matches over the years, and I expect something similar."