The result evened the series between the two 8-8 and ended Federer's streak of reaching the final in eight straight tournaments — going back to May.

"It's not easy being aggressive against him when you're 3 meters (10 feet) behind the baseline," said Federer, who lost to the Argentine in the final of the Madrid Masters on Oct. 21.

"He's got a phenomenal backhand and can dictate play from both sides," said Federer, who lost for the eighth time this season. Guillermo Canas and Rafael Nadal also have beaten Federer twice each while Novak Djokovic and Filippo Volandri also have beaten the Swiss star.

"I wish conditions were a bit faster because indoors is supposed to be fast," Federer said. "Not here, I guess."

Nalbandian didn't complain.

"Well, it's different," Nalbandian said. "Over there (in Madrid) it's a little faster."

He next plays fifth-seeded David Ferrer of Spain, who advanced after beating 12th-seeded Tomas Berdych 6-4, 6-2.

After beating Federer in Madrid, Nalbandian was eliminated in the first round of last week's event in Basel, Switzerland. The week before Madrid, he was eliminated in the second round in Vienna.

"Federer's the No. 1 in the world," Nalbandian said. "You always have to be at 100 percent. I was, just like in Madrid."

Nalbandian wasted five set points by shanking balls long or into the net.