Australia star Tim Cahill has asked fans to keep the faith heading into the final group stage match on Wednesday (Thursday morning AEST).

The Socceroos need to defeat Serbia and hope Germany take down Ghana in the final Group D matches and Cahill admits strong support from the Australian fans will help the players immensely.

The Everton midfielder missed the 1-1 draw with Ghana on Saturday night due to suspension but sat with the fans and said the atmosphere was unbelievable.

"I was sitting with the fans yesterday and was so proud to see what they had to offer," Cahill said at training Sunday. "You would've thought we were playing the game in Australia.

"So for us, thanks for your support and obviously keep the faith because we believe in ourselves."