Cahill - the Socceroos' all-time goalscorer - has made over 100 caps for Australia. 

However, approaching 38 years of age, his time in the national team is winding down. 

And with the possibility of Australia not making the 2018 World Cup in Russia, Cahill knows in the back of his mind this may just be his last game for the Socceroos. 

But he's not considering it as a possibility at all.

"Not thinking about it," Cahill said, asked if Wednesday could be his last game for Australia.

"That's the different between me and everyone else, I don't think about the negatives.

"This is so important for our country. 

"For me, what's driving me is Wednesday night. It's the same thing against Syria, to win the game if selected."