Garang Kuol had long been hoping for his moment to announce himself to the football world and on Sunday he went agonizingly close to etching his name in World Cup folklore.

Kuol became the youngest player since Pele to feature in a World Cup knockout match when Graham Arnold brought him off the bench in search of two late goals after Lionel Messi and Julian Alvarez gave Argentina a comfortable lead in their last-16 match.

Craig Goodwin halved Australia's deficit with a deflected strike before Kuol went so close to sending the game to extra time.

Receiving a cross at the back post from the left hand side, Kuol set himself with a glorious first touch and, shooting on the half turn, put all his strength behind a right-footed strike at goal.

However, Argentine goalkeeper Emiliano Martinez was equal to the chance and stretched an arm out to parry and break Australian hearts.

There are lofty expectations surrounding Kuol - who will join Premier League side Newcastle United in January - and Socceroo's fans took to Twitter to lament the spurned opportunity, with one fan describing it as 'the biggest what if moment in Australian football for a long time.'

Another said: 'Imagining a reality where Garang Kuol scores there.'

A third added: 'That may have been a missed opportunity to be a hero, but I hope Garang Kuol goes on to have bigger moments in his career'.

Toon legend Alan Shearer praised Kuol's cameo, crediting Martinez with a superb save rather than a poor effort from the 18-year-old.

'He came on as a substitute and put himself around didn’t he,' he said. 'He let the defenders know he was there and we were thinking, is this his opportunity.

'The goalkeeper deserves a lot of praise for being quick out there. Martinez blocks it, the last kick of the game virtually there.'