Captain Michael Clarke demands an era of ruthless rule after describing Australia's ascension to the top of Test rankings as his most satisfying day in cricket.
Clarke has challenged his Test players to achieve greatness with a period of sustained world dominance.
"I don't think I have had a more satisfying day or feeling in my career," Clarke told reporters in Sydney on Thursday.
"It takes a big effort to get to No.1 in the world in any sport, there's no doubt about it.
"But it's even harder to stay there and great teams find a way to stay there. So that is our job, that is our priority.
"We have worked exceptionally hard to get here and we have to work harder to stay here."
Australia also remain top of one-day international rankings, but were in sixth spot on Twenty20 rankings, on fresh figures released by the International Cricket Council on Thursday.
Clarke couldn't hide his delight at Australia reclaiming the No.1 Test mantle for the first time in five years.
Just 14 months ago, Clarke's team was derided as the nation's worst ever after a 4-0 Test series loss in India.
The brickbats after the March 2013 Indian tour were followed by a 3-0 Ashes defeat in England, a series preceded by the sacking of coach Mickey Arthur.
"Two years ago, we were ranked No.5 in the world," Clarke said.
"As captain of the team, I remember, it's still in the front of my mind, what was written and said about us once we came back from India: we were named the worst Australian team to ever tour India.
"And as captain that is the last thing you want to hear. That breaks your heart.
"So to enjoy today and see the other side ... I'm extremely proud."
Australia took top Test billing from South Africa, who had held that ranking since August 2012.
The result comes after Australia defeated the Proteas 2-1 in South Africa in February-March, and a stunning 5-0 Ashes sweep on home turf last summer.
"The two things that I have spoken about with this team over a long period have been hunger and attitude," Clarke said.
"And you can see the hunger inside individual players, and the attitude. Obviously there's a reason why we stand here as No.1 in the world."
