BASEL, Switzerland — James Blake had 18 aces and rallied from a set down to beat Oscar Hernandez 6-7 (4), 6-2, 6-4 today and reach the quarterfinals at the Swiss Indoors.

"I was serving well and that got me out of a lot of trouble," Blake said.

Second-seeded David Nalbandian beat Kristof Vliegen 6-4, 5-7, 7-6 (4). The 26-year-old Argentine broke Vliegen to take the first set. The Belgian broke in the 11th game of the second set, and won it on his fourth set point with a service winner.

Nalbandian, the 2002 champion and two-time runner-up since, lost his first match point at 6-5 in the decider when Vliegen hit a running backhand winner from wide of the court. He clinched when Vliegen failed to control a strong service return.

Juan Martin Del Potro, the No. 3 seed, made just four unforced errors as he cruised past Stephane Bohli 6-3, 6-3, putting him on course to meet his Argentina Davis Cup teammate in a semifinal.

Simone Bolelli beat Marcel Granollers 6-4, 6-2.