Ledesma was an assistant to Cheika for three seasons before returning to his native country to coach the Jaguares in Super Rugby.

He was appointed as coach of Los Pumas last month and, in just his fourth match in charge, Ledesma has delivered a result that will be remembered as one of the great triumphs of Argentinian rugby.

Saturday's 23-19 Rugby Championship win was the first victory for Argentina on Australian soil in 35 years.

Ledesma admitted it was a "bittersweet" feeling to know it will also increase the pressure on Cheika and his former colleagues.

"That was my team. Still is, in one way," Ledesma said.

"And the bond that we have is not going to disappear from one day to the other."

But Ledesma was adamant fortunes would change soon for the Wallabies, despite what angry supporters might be feeling.

Ledesma was confident that Cheika had done enough heavy lifting behind the scenes for Australia that success would eventually follow.

"I know it's difficult to see when you're not winning but the depth that Michael has brought to Australian rugby, the age of the front-rowers out there, second-rowers out there, even wingers, centres; that wasn't the case a couple of years ago," he said.

"The level of fitness of the boys (is higher) compared to a couple of years ago.

"The way he united the head coaches of Super Rugby to work together physically and technically, the basic skills and stuff like that... it's going to pay, 100 per cent it's going to pay (sooner) than later.

"I know that."

Australian Associated Press