"I was really impressed by the way this team responded after the [47-26] win. They've just given themselves an opportunity. Everything lies ahead now," he said.
While Eden Park had been a hard place for Australia especially to win, he said that once the whistle blew it was a whole other game.
QUICK TAP: ALL BLACKS NAME TEAM FOR BLEDISLOE CUP DECIDER
"You've just go to perform and got to believe. They're going to respond, the All Blacks, but it comes back to basics.
"You've got to keep playing against the All Blacks, you never just put the cue in the rack, so to speak, you've actually got to keep playing and that's got to be the attitude," he told rugby.com.au.
Gregan has been working with the Australian coaching staff. He has been concentrating on fundamentals with the halves and he hopes his work will contribute to the Wallabies playing instinctive rugby.
"It's just a philosophy around nailing the fundamentals and everyone understanding what they're trying to do.
"It's not complicated, but it's just reinforcing all those really important things that you do.
"I think every sport's similar, if you haven't got good basics, it really impacts on your ability to perform."
Gregan said the players at the top level were good and they had good instincts so getting the fundamentals and basics right meant they could then look to utilise their full set of skills.
"I view it as a golf swing – if it's just a little bit off, it just needs a little correction and then they're away.
"You don't get many opportunities when you play against a team like the All Blacks, so you've just got to trust your instincts and the players around you, and I think that was shown last week.
"And they're always going to fight, so you can't get too far ahead of yourself, you can't reflect on something that's just been, you've got to be very present when you plan and that requires having good instincts, totally.
"But there's a massive challenge ahead this week.
"It's a very important match which you want to be trying to do your best in – which they will do. But you want to get the right result, which is a win," he said.
Australia had been denied so often in the past because the chance they now had for success was so hard to do.
"The World Cup is [important] too, there's no doubting that, but the World Cup's not this Saturday," he said.
"[The Bledisloe] is a good one because it's hard to win. And they don't like to give it up, and we don't want to give it up either.
"It's a big trophy and it means a lot to both countries. It's a special one to have but you've got to work really, really hard to get it," he said.