Roger Federer was in spectacular form as he defeated Italy's Daniele Bracciali 7-5, 6-3 on Wednesday to reach the quarter-finals of the Dubai Open.

The Swiss's conqueror in last year's final, second seed Rafael Nadal was less impressive. The Spaniard was stretched to a final set tiebreak before he overcame Russia's Igor Andreev 6-2, 3-6, 7-6.

Federer literally brought Bracciali to his knees in the second set after hitting a spectacular shot between his legs for a winner down the line and a 5-2 lead. As the crowd roared its approval, Bracciali knelt on one knee as Federer passed him on the way to his chair.

"I liked it," said Federer. "It was a shot I haven't hit in a very, very long time. I've had great shots over the years and that was definitely one of them. Through the legs from very far back in the court for a winner, it's just great."

Bracciali held his nerve in the first set and looked as if he would take the world number one into a tiebreak.

But at 6-5 up and 30-30 on Bracciali's serve, Federer suddenly raised his game, hit a superb forehand volley and followed up with a backhand pass to break.

Federer kept up the momentum in the second to grab a 2-0 advantage and never looked back.

"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."

SPECTATOR COLLAPSE

Nadal held the upper hand in the first set against the hard-hitting Andreev, breaking in the opening game and then again to lead 4-1.

But he missed a golden opportunity to take total control of the second set when he failed to convert three break points at 3-3. A double-fault in the next game then gave Andreev a break for 5-3.

Play was held up for several minutes at 4-4 in the third set when a spectator suffered a nose-bleed and collapsed.

On resumption Andreev needed four game points to reach the tiebreak. A broken string on Andreev's racket failed to distract Nadal and he wrapped it up 7-2.

"The match very, very close all the time. I'm very happy today," said Nadal, who has failed to reach a tournament final since last year's Wimbledon showdown against Federer in July.

"It's an important victory for me. For sure it's important to win one match like this. To win a tiebreak in the third set is very good for my confidence."

Fifth seed Tommy Haas kept up his winning run following his success in Memphis on Sunday by reaching the last eight with a 7-6, 6-3 win over Florent Serra.

Third seeded Nikolay Davydenko had no such luck.

Having struggled to beat Moroccan qualifier Younes El Aynaoui in the first round, the Russian slumped 4-6, 6-4, 6-2 defeat by Belgian Olivier Rochus.

Sixth-seeded Czech Tomas Berdych lost 7-6, 6-3 to last weekend's Rotterdam champion Mikhail Youzhny.