In a match devoid of much goalmouth action, Argentina were on the brink of victory after going 3-1 up in the shootout, but missed three of their next four penalties to bow out
The match itself was starved for chances during the 120 minutes, but the European side managed to come back from a 3-1 deficit in the shootout to send their South American opponents crashing out of the competition.
Portugal came into the match with an imperious defensive record, boasting a clean sheet in each of their previous four games. Argentina’s defence was almost as impressive, having only been breached through a penalty during their 2-1 victory over Egypt in the last round.
Portugal had their first genuine chance after 20 minutes when Caetano was put clean through on goal, but he fired straight at Esteban Andrada, who tipped it over the goal. Erik Lamela also came close for Argentina when he curled a 20-yard free kick just over the crossbar.
The urgency of the game died down soon after and, as expected, the defensive organisation of both teams began to take effect. Play frequently stagnated and both teams were largely restricted to speculative efforts from outside the box. However, the shooting boots were clearly left at home, with a succession of efforts blazed harmlessly over the bar as the first-half petered out.
The match continued in much the same fashion after the interval, with clear-cut opportunities hard to come by. Argentine substitute Juan Iturbe made an immediate impact on the hour mark when Michael Domingues fumbled his effort from 20 yards out, but no one was on hand to attack the rebound.
Both teams failed to find an opening as the second-half wore on, and it was perhaps inevitable that referee Peter O’Leary signalled for extra-time. However, chances remained at a premium throughout the 30 minutes, and it became obvious that penalties would be needed to find a winner.
Portugal seemed dead and buried after Andrada saved from Danilo Pereira and Roderick Miranda to send Argentina up 3-1 in the shootout, but Leandro Pirez, Emanual Ruiz and Nicolas Tagliafio all missed to send the Europeans through to the semi-finals.
Portugal will face the winners of Sunday's France-Nigeria quarter-final in four days’ time for a place in the final.