Defending champion Toby Price overcame a tricky day to lead the way and stake his claim in the opening stages.
Matthias Walkner was initially credited with second place behind his KTM team-mate, but was subsequently handed a five minute penalty for a losing his time card and dropped to 13th place for the stage, handing second and third to Paulo Gonçalves and Xavier De Soultrait as the motorcycle category began to take shape.
And in the quads Pablo Copetti gave the home fans in Argentina a boost with the stage win, and was followed closely by Nelson Sanabria, with Axel Dutrie just over five minutes off the lead time.
