Lopez defeated Lukas Lacko 6-3, 7-6 (7-3) in the final first-round match of the event. He lost his serve once in the first set but countered that with three breaks against Lacko. Lopez then handled all five break points he faced in the second set to advance.
The second round began Wednesday with wins by seventh-seed Julien Benneteau and Vasek Pospisil.
Benneteau was a 7-5, 6-2 winner over Matthew Ebden, losing 15 points over his 10 service games. Pospisil stopped Michael Yani 6-3, 7-5 without dropping serve. He won nearly 70 percent of the points on serve with an attack that included nine aces.
Denis Istomin ousted sixth-seeded Pablo Andujar 6-3, 6-2 in a first-round match. Istomin took nearly as many points -- 24-to-25 -- on Andujar's serve as Andujar won.
The other first-round results Wednesday saw Alex Bogomolov Jr. beat Dominic Inglot 7-5, 6-3; Nikolay Davydenko getting past Sanam Singh 7-5, 6-4; and Alejandro Falla advancing when, after Falla went up 7-6 (7-4), 4-2, Rajeev Ram retired.