Berlocq was the only seeded player in action on Day 1 and he responded by besting one-time Houston runner-up James Blake of the United States 6-4, 2-6, 6-1.
Querrey -- another former runner-up -- also found his way into the second round, firing six aces en route to an easy 6-1, 6-4 victory over France's Eric Prodon.
German Bjorn Phau was leading 6-1, 3-0 in his first-round match when Argentine Diego Junquiera retired.
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