Gregan took over from Eales in 2001 after Australia had won the World Cup and despite five years at the helm says he is still excited by the prospect of leading his country for the 55th time.
Gregan told the Courier Mail: "The challenge is still there for me. As a captain you want to set the example and I hope I've done that."
But Gregan still has one more mountain to climb - winning a World Cup as captain.
And with the scrum-half still playing well and enjoying the support of Wallabies coach John Connolly, he may very well break England centre Will Carling's record of 59 Tests as captain during Australia's 2007 World Cup campaign.
Connolly said: "George is one of Australia's greatest ever players, and part of that is because he has never stopped working hard.
"I spoke to him earlier this season about adding a bit to his running game and being sharper about the base. He's taken that all on board."
Connolly also believes that Gregan's success as captain is down to the respect he has from his team-mates.
"George is a pretty private guy but quite inspiring," Connolly said.
"His words in the dressing room to the team before our last Test win over South Africa were the kind of words where nothing else needed to be said. He got it just right."
The Wallabies go into the clash with New Zealand needing to win the match to have a chance of winning back the Bledisloe Cup after the All Blacks won the opening match in the series 32-12 in Christchurch on July 8.
Connolly named the Australian team on Wednesday with a nine-man reserves bench but on Friday afternoon he trimmed it down to seven by omitting flanker Wycliff Palu and prop Al Baxter, who has a shoulder injury.
Meanwhile, Wallabies rugby legend David Campese has underlined Australian centre Matt Giteau as the player who could turn the game in the Wallabies favour.
"Matt Giteau coming back at inside centre for Mat Rogers, who played in the No.12 jumper in game one, is a major plus for Australia," wrote Campese in the Daily Telegraph.
"Giteau showed against South Africa what he can bring to an attack with his footwork and passing game."