The 15-6 victory at a packed and noisy Eden Park has placed the Irish in control of Pool C and on the brink of qualification for the quarter-finals.
Their greatest World Cup win and first against Tri-Nations opposition in the competition indicates they are capable of making a genuine impact in New Zealand.
But Ferris, who starred among an outstanding Ireland back row, insists they have yet to reach full potential despite humbling the second favourites.
"We didn't peak against Australia. There's definitely a lot more attacking ability to come from us," he said.
"This wasn't a one-off performance, we knew this was brewing and we're glad it happened against Australia.
"We'll be targeting a big win on Sunday against Russia and a big win against Italy the weekend after that.
"If we keep playing like we did against Australia, hopefully we'll be able to maintain this and go further in the tournament.
"We're still taking it game by game. We said at the start of the World Cup we just want to get out of the group.
"But our performance against Australia has put us in a good position."
Ferris was responsible for the highlight of the match towards the end of the first half when he grabbed Will Genia at the back of yet another crumbling Wallaby scrum and carried him 10 yards.
The hunger of Ireland's pack was evident as they piled in behind the Ulster hardman, rattling Australia. The youngest squad in the World Cup was taught a lesson by the oldest.
Considering Ferris was playing only his third match since sustaining a serious knee injury in January, it was a phenomenal performance that saw him wreak havoc throughout.
"The injury isn't in the back of my mind at all. I was in the best shape of my life for the 2009 Lions tour," he said.
"But now I have three 80-minute performances under my belt and I'm starting to pick it up.
"I'm playing in a great team. Fingers crossed I'll keep improving."
Heroes in Ireland's pack were everywhere, from the brutally effective Sean O'Brien to marauding Munster colossus Paul O'Connell, from man of the match Cian Healy to destructive tighthead Mike Ross.
Ferris revealed the inspiration for victory came from senior players such as O'Connell and Brian O'Driscoll, who are playing in their final World Cup.
"You look at them in the changing room before a match and you see how much it means to them," he said.
"Paul O'Connell started with tears in his eyes, telling us how he will attack the game in the first 10 minutes. You take heart from that.
"I'm a fairly quiet man when it comes to the changing room and on the pitch. I listen to those guys and feed off them."
The World Cup may still be in the pool stages, but victory has offered sight of the final with the Six and Tri Nations teams likely to be separated until the October 23 showpiece.
Facing the likes of Wales and England in the knockout stages will hold no fear for Ireland, though fly-half Jonathan Sexton insists celebrations over beating Australia must subside.
"We don't want this to be our final. Our goal was to get to the quarters," said Sexton.
"We're halfway there because now the pool is in our control. Two more wins and we're there.
"Once we get to the quarter-finals we can sit down and re-evaluate everything."
Ireland had lost all four World Cup warm-up internationals and failed to convince against the USA last weekend, yet produced the type of expectation-defying display that is becoming their trademark.
"We always had belief even though lots of people wrote us off," said Sexton.
"Our form was poor coming into the competition but people didn't notice that we used a lot of players and concentrated on getting people match-fit.
"Even the guys who weren't coming with us, we tried to get them match-fit so that if there were any injuries they'd be ready.
"We were chopping and changing the team and that stopped us getting the continuity. Hopefully we can build on this now."
Gilbert has released a new line of rugby cleats. The Gilbert Virtuo 8S is part of the exciting new product. Check it out.
The Barbarians are one of the top invitational rugby sides with a long history and classic rugby jersey.
The Nike Tiempo is a solid rugby cleat and one of few styles still made from full-grain natural leather.
The Lions get ready for their matches with this green training jersey. It's what the players wear. Get in the Gear!
A cool looking all black rugby cleat with the high performance adidas is known for. Get in the Gear!
Wear the crest of the British and Irish Lions on your t-shirt. A great look for the summer.
The Lions are ready to get their Australia tour underway. They arrive in Perth on Monday.
The New Zealand All Blacks training jersey for 2013/14. Get in the Gear!
The USA Rugby Pro Alternate rugby jersey is perfect for any fan of the Eagles. Get yours to wear during the summer Test matches.
The NEW All Blacks 2013/14 jersey has arrived at World Rugby Shop. Dare to wear the colors of the All Blacks.