The Argentinian, the only seed in action, recovered from a shaky second set to clinch the match 6-4 2-6 6-1.

Blake had led 1-0 in the deciding set before Berlocq rattled off six games on the bounce to seal the win.

The result means Blake, the former world number four, has yet to taste victory in 2012.

Next up for Berlocq is Bjorn Phau, who was 6-1 3-0 up in his first-round match when Diego Junqueira was forced to withdraw because of a hip problem.

Former finalist Sam Querrey is also through to the next round after the American saw off Eric Prodon 6-1 6-4.