Hwang Ui-jo scored the only goal of the game as the Caltex Socceroos went down 1-0 to Korea Republic in Friday evening's international friendly.
Australia created several good opportunities against the Taeguk Warriors in Busan - and hit the post early on through Mitch Duke - but fell behind when substitutes Hong Chul and Hwang combined to give Korea Republic the lead late in the second half.
Duke - leading the line in his first appearance for the Caltex Socceroos since September 2013 - came within centimetres of capitalising on an enterprising start from Graham Arnold's side with a glancing header from Brandon O'Neill's corner which bounced off the foot of the post.
The Western Sydney Wanderers forward had earlier flashed a warning shot wide, while FC Midtjylland attacker Awer Mabil stung the palms of Korea Republic 'keeper Kim Seung-gyu after volleying Craig Goodwin's clipped pass across goal at the back post.
Vissel Kobe custodian Seung-gyu was by far busier than opposite number Andrew Redmayne, with the debutant custodian not facing a single shot from Paulo Bento's Korea Republic until he was made to collect a deflected free-kick from Tottenham Hotspur attacker Son Heung-min on the hour mark.
However, Hwang - who scored in November's 1-1 draw with Australia in Brisbane - made himself the 75th minute match-winner in Busan by latching onto Hong's cross at the near post.