Fresh off his title in Sao round victory at the Copa Claro tennis event.
The second-seeded Almagro fought back to beat Italian Potito Starace 4-6, 6-3, 7-6 (7-4) in 2 hours, 7 minutes on the red clay at Buenos Aires Lawn Tennis Club.
Almagro topped Argentine favorite Juan Ignacio Chela in last year's Buenos Aires finale and bested Italy's Filippo Volandri in last week's title tilt in Sao Paulo.
Up next for the world No. 11 Almagro will be Argentine Federico Delbonis.
Meanwhile, third-seeded Frenchman Gilles Simon handled Portuguese Rui Machado 6-3, 7-5, fifth-seeded Argentine favorite Juan Monaco leveled the aforementioned Volandri 6-1, 3-1, retired, and seventh-seeded Spaniard Fernando Verdasco dismissed France's Eric Prodon 6-4, 6-1. Monaco titled here in 2007 and was the runner-up in 2009.
An upset came when Spaniard Albert Ramos upended an eighth-seeded Chela 4-6, 6-3, 6-4.
Additional Day-2 wins came for the qualifier Delbonis, Russian qualifier Igor Andreev and Frenchman Benoit Paire.
The 2012 Buenos Aires champion will earn $82,900.