Ireland captain Brian O'Driscoll celebrated his first World Cup win over Australia but warned that the job was "only half-done."
The Irish now aim to finish as Pool C winners and potentially set up a quarter-final clash against Wales.
"It is a performance we knew we had in us. We had to dig deeper than we had done in the last five games," said the skipper after Ireland's 15-6 victory.
"We will enjoy this, but let's not forget that we have two more games."
O'Driscoll revealed that injured hooker Jerry Flannery had played an important role in rallying the side in the build-up to Saturday's game.
Injury-plagued Flannery was ruled out of the remainder of the tournament in midweek by a calf problem.
"There were some very passionate words said by guys who weren't even in the 22. That's where it came from," added the Ireland captain.
"There were some poignant moments throughout the week.
"I don't think a lot of guys will forget Jerry Flannery handing out the jerseys yesterday at the captain's meeting."
Ireland coach Declan Kidney also refused to get carried away with the victory.
"I was pleased with the way we went about out business. We managed to stifle a very good Australian side," he said.
"I think our scrum is getting a little stronger. We still have a little bit of work to do. The work really starts now."
He did, however, add: "It's the fifth time we have played Australia in the Rugby World Cup and you get a bit fed up with losing."
Lock Paul O'Connell, who captained the Lions on their tour of South Africa in 2009, added: "Today we played to our potential.
"It's just a pool game for us. All the games from now on in are big games."
Australia had their own injury problems for the match with influential flanker David Pocock and hooker Steven Moore ruled out and they struggled in the scrums throughout as the Irish front five dominated.
"Ireland were very effective. They defended really well and did not allow us to recycle the ball. It was effective," Australia coach Robbie Deans said.
"We would have liked more field position. Our decision-making was not always great."