Carreno-Busta, No. 228 in the world, had a pair of breaks in each set of a 6-3, 6-4 win over Benneteau. Carreno-Busta finished off half of his four break opportunities in the second set to claim just his third main-draw win of the year.
Gastao Elias, a wild-card entrant, eliminated seventh-seeded Horacio Zeballos 6-3, 4-3 by taking nearly half (31-of-65) of the points when receiving serve.
Other first-round results Tuesday saw Victor Hanescu beating Rui Machado 6-4, 6-4; Alejandro Falla getting past Andrey Kuznetsov 7-5, 6-4; Robin Haase taking out Pablo Andujar 4-6, 6-2, 6-3; Paolo Lorenzi stopping Niels Desein 6-3, 4-6, 6-2; and Albert Ramos advancing over Carlos Berlocq 7-6 (7-4), 2-6, 6-3.