The Lions ace came on as a late substitute for the Socceroos during their international friendly against South Africa at Loftus Road.
Cahill had been prevented for playing for his home nation after turning out for Samoa's U-20 side at the age of 14 while on a family vacation. Despite assurances that it would not affect his future selection, FIFA ruled that he was ineligible to play for Australia. But after a long legal battle, FIFA relaxed their rules over selection and Cahill was given the all-clear in 2003.
Australia won the game 1-0. Fellow Lion Kevin Muscat was rested with this weekend's FA Cup Semi-Final in mind.