Australia coach Guus Hiddink paid tribute to his side's fighting spirit as the Socceroos twice came from behind to secure a place in the second round.
Harry Kewell's late equaliser ensured a 2-2 draw that sent the Socceroos through and eliminated Croatia.
And Hiddink said: "They scored a terrific free-kick and we were 1-0 down. But I know this team has enormous mental power to be able to come back.
"I know this team, this team can react always and it did again this time."
Australia now face Italy in the second round after reaching the knockout stages for the first time.
Brazil topped Group F after taking maximum points from their three matches, while the Socceroos finished second with four points.
We are a family out there and we are very disciplined
Australia needed to at least draw their final game against Croatia to progress.
It proved to be a match full of incident, a delighted Hiddink saying: "This was a terrific game. It shows why the beautiful game is so exciting."
But it was his side's gutsy play that impressed him most.
"This team has a lion's heart, to fight until the end," said the Dutchman. "They are very competitive, they never give up whatever happens."
Tim Cahill praised his Merseyside rival Kewell and highlighted the spirit in the team.
"This is very special. Harry was very tired but he did it," said the Everton midfielder.
"We fought to the end. We are a family out there and we are very disciplined. Whatever anyone throws at us, together we are stronger.
"We are confident. With each game we have shown what we are capable of."