Cabrera, the 2001 and 2002 champion, had an eagle, four birdies and two bogeys on the Buenos Aires Golf Club course.
Argentine amateur Esteban Martinez was two strokes back at 68 along with countrymen Andres Romero and Sebastian Fernandez, England's Ben Parker, Colombia's Diego Venegas and France's Bertrand Coathalem.
The tournament is sanctioned by the Tour de las Americas, the PGA European Challenge Tour and the TPG of Argentina.
Copyright 2007 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.