Federer advances to quarterfinals, Karlovic ousts Blake at Swiss Indoors

Roger Federer beat Juan Martin Del Potro 6-1, 6-4 Thursday to advance to the quarterfinals at the Swiss Indoors, his home tournament.

Federer, seeking his seventh title this year, has won three Grand Slams this season but lost in the Madrid Masters final Sunday.

"I came out of the blocks really fast today and he missed some shots at the start," Federer said. "It's a little bit difficult with so many family and friends here, but I am beginning to get comfortable."

Federer will next play Nicolas Kiefer , who beat Stefan Koubek 6-3, 6-2.

Ivo Karlovic served 24 aces in beating fourth-seeded James Blake 4-6, 7-6 (4), 6-4 to also reach the quarterfinals.

The 6-foot-10 Karlovic, the tallest player on the ATP tour, is having his best season with three titles and is also second on the career list for aces in a season behind Goran Ivanisevic .

"I could serve with a basketball," Karlovic said when asked if he had trouble with somewhat heavier balls used at the Swiss Indoors.