A dominant scrum, a more energised performance and 19 points from the boot of skipper Filippo Buscema saw Italy upset Argentina in Pool A.
Italy had sent out a second-string outfit on Monday in their 63-3 loss to England, so this was their targeted game. Argentina, wearing red to avoid a blue clash, were flat and relied heavily on the accurate boot of No10 Patricio Fernandez at Albany.
At the death, Italy won a critical turnover after Argentine pressure off a lineout and duly and deservedly won their first JWC victory since they hosted the tournament in 2011.
Their first try of the tournament was a cracker, a well-worked scrum move seeing left wing Lorenzo Maria Bruno inject himself and some flypaper hands led to fullback Gabriele di Giulio crossing after just six minutes.
Argentina's reply was swift and deadly, tighthead prop Tomas Ramirez latching on to the end of a lineout drive for his try.
First-five and captain (for Argentina) Patricio Fernandez was sinbinned for constant offside. Italy were quick to capitalise when Bruno left his marker for dead to touch down in the corner.
Argentina manufactured a try in the corner, finally confirmed by the TMO, to No12 Bautista Ezcurra to help tie it up at 20-all. Buscema, Italy's captain and general, popped over a dropped goal, which was ultimately the difference.
Italy 29 (Gabriele di Giulio, Lorenzo Maria Bruno tries; Filippo Buscema 2 cons, 4 pens, dg)
Argentina 26 (Tomas Ramirez, Bautista Ezcurra tries; Patricio Fernandez 2 cons, 4 pens). HT: 17-13.