Ireland avenged their quarter final playoff defeat by Argentina at Rugby World Cup 1999 with a hard fought 16-15 victory at Adelaide Oval.
In doing so Ireland ended Argentina's hopes of a quarter final berth by confirming that they and defending champions Australia would progress from Pool A.
Both teams have 14 points from their three games, Australia occupying top spot by virtue of their surperior points difference, and meet in Melbourne's Telstra Dome next Saturday to decide who will win the Pool.
The arrival of Ronan O’Gara, who replaced David Humphreys just before the hour mark, proved the turning point in the game with the fly half initiating a running game.
With O’Gara pulling the strings the Irish back line of Denis Hickie, Kevin Maggs and Brian O’Driscoll began to make telling breaks into the Argentinian half.
However Ireland were unable to breach the Pumas try line and instead had to settle for two penalties from the boot of O’Gara to edge them into a four point lead with 15 minutes remaining.
The game had opened up in the second half, which began with Ireland leading 10-9, with both sides happy to run with the ball in hand and Argentina regaining the lead with a Ignacio Corleto drop goal.
The Pumas had made by far the better start to a match upon which their Rugby World Cup 2003 futures rested on with prolonged pressure in the Ireland 22 resulting in a seventh minute penalty by fly half Gonzalo Quesada.
Argentina dominated possession and territory in the early stages before a pick up and charging run by Ireland captain Keith Wood saw Alan Quinlan over for a 20th minute try.
However that was to be the flanker's final contribution in a passionate encounter with Quinlan dislocating his shoulder in scoring the try.
Humphreys converted the try and kicked a penalty.
Argentina: 15
Penalties: Quesada (3)
Drop Goals: Quesada, Corleto
Ireland: 16
Tries: Quinlan
Conversions: Humphreys
Penalties: Humphreys, O’Gara (2)