The 27-year-old will play eighth-seeded compatriot Carlos Berlocq, the world No. 81 who lost to Nadal's doubles partner Juan Monaco in last year's final at Vina del Mar.
World No. 19 Juan Monaco, Argentina's No. 1 in the absence of Juan Martin del Potro, gave his country a lifeline by beating 13th-ranked Gilles Simon 7-6 (7-2) 6-2 6-4 on the red clay.