Argentine Horacio Zeballos took down top-seeded countryman David Nalbandian during the second-round action at the $450,000 Movistar Open, the first clay-court event on the 2011 ATP World Tour calendar.

Zeballos defeated Nalbandian 6-2, 7-5 in 80 minutes at Las Condes. Making his season debut on the ATP World Tour, Zeballos fired eight aces past Nalbandian to advance to the quarterfinals.

Nalbandian, who did not record an ace, fell to 6-3 in 2011, tsn.ca reported.