Berlocq took early charge with a 5-1 lead in the first set and then had to hold on to win the opening set. Blake easily won the second set with Berlocq getting his ailing calf wrapped before losing the final game of the second set.
Berlocq said he felt tightness in his left calf. He left the court briefly before the final set to get more treatment.
Instead of fading, Berlocq was energized from the start of the final set. Blake held serve in the first game, but then Berlocq won six straight games.
Berlocq broke Blake in the final game at love. He hit a backhand return of service winner at the first match point.
Berlocq said he first felt pain in his left calf 10 days ago and felt it tighten again early in Monday night’s match.
Sam Querrey of the United States, a 2010 finalist, beat Eric Prodon of France 6-1, 6-4 in another first-round match.
Former champion Tommy Haas withdrew with a right knee injury prior to a qualifying match.
Top-seeded Mardy Fish, who withdrew from Davis Cup play last week because of fatigue, has a bye into the second round and will play his first match on Thursday.
In Casablanca, Morocco, Albert Ramos beat Pere Riba 6-2, 6-3 in an all-Spanish match in the first round at the Grand Prix Hassan II on Tuesday.
The seventh-seeded Ramos broke five times and will play Victor Hanescu of Romania, who led 6-2, 3-0 against Malek Jaziri when the Tunisian retired.
Jeremy Chardy saved eight of nine break points to defeat Federico Delbonis of Argentina 6-4, 7-5. The Frenchman will meet top-seeded Florian Mayer of Germany.
