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.
Top-seeded David Ferrer of Spain breezed to a 6-1, 6-0 win over Argentine qualifier Andres Molteni, who was making his ATP World Tour main draw debut ranked No. 237. Ferrer, who was the runner-up here in 2010, has a 9-1 match record on the season. He opened the year with a title in Auckland.
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.
Argentine David Nalbandian, who was the Buenos Aires titlist in 2008, cruised to a 6-2, 6-3 win over American lucky loser Wayne Odesnik.
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.