Sweeting, who won the Houston title last year with a final victory against Kei Nishikori of Japan, had to save two set points at 5-6 in the second set against the Brazilian. The American didn’t let Mello back in the match and after winning the tiebreak, he set up a second round clash against either Ivo Karlovic or Bobby Reynolds.
Another American Michael Russell booked his place in the second round, beating the Spaniard Daniel Gimeno-Traver 2-6 7-5 6-1.
In round two, Russel will play no.1 seed Mardy Fish, who had a first round bye.
Also through to the next round is Paolo Lorenzi of Italy, defeating Wayne Odesnik 6-7 (3) 6-2 6-3 and the Argentine qualifier Horacio Zeballos, who overcame the Romanian Adrian Ungur 6-3 6-3.