Sweeting, who was considered a surprise winner of the Houston tournament last year, moved on to the second round after ousting the Brazilian 6-3, 7-6 (8-6).
Sweeting served six aces and saved 7-of-9 break point opportunities in the 108-minute match.
Also advancing was Houston native and qualifier Michael Russell, who rallied to beat Spain's Daniel Gimeno-Traver 2-6, 7-5, 6-1. Russell will face top-seeded Mardy Fish on Thursday.
Other first-round winners were Igor Kunitsyn of Russia, Tatsuma Ito of Japan and Italian Paolo Lorenzi.
Astronomers offer more expansive view of universe
Beautician charged with giving client fatal silicone butt injection