Argentina narrowly edged out Scotland in a wet Wellington Regional Stadium to edge closer to a quarter-final place.
In a tightly contested first half, Scotland went in ahead 6-3 at the break thanks to penalties from Chris Paterson and Ruaridh Jackson.
A Felipe Contepomi effort drew the sides level before drop-goals from Jackson and Dan Parks gave the Scots a six-point lead.
The Pumas edged ahead however thanks to the only try of the game.
Lucas Gonzalez Amorosino went over after a solo run and Contepomi converted.
Parks sliced a late drop-goal effort in an attempt to snatch victory and Argentina won the ball back to clear to touch.
Scotland next face England on Saturday while Argentina, who are now favourites to qualify in second in Pool B, face Georgia the following day.
