France's defence was left traumatised during the final quarter of their bizarre 43-31 triumph in Paris as Ireland gave a tantalising glimpse of the possibilities.
A hugely gifted backline including Brian O'Driscoll, Geordan Murphy, Gordon D'Arcy and Shane Horgan cut the French to ribbons, but never scaled those heights again.
The forwards have provided plenty of grunt since, namely against Scotland and England, but O'Driscoll and co have been subdued, showing only flashes of brilliance.
O'Connell knows the summer tour to the southern hemisphere will supply the true gauge of Irish progress and feels the inspiration for further glory will be provided by the backs.
"We'll know how far we've come when we go down to the southern hemisphere and play Australia and New Zealand," he said.
"We toured both countries three and four years ago but without as good a side as we have now and nearly beat them. We'll have to try and do the same again.
"A Triple Crown is brilliant but the big test will be the southern hemisphere. Look at the talent we have. Ireland have always had a good pack which can mix it with teams.
"But with the backs we have we should be kicking on from a Triple Crown. We need to start looking at Grand Slams and winning away from home in the southern hemisphere.
"We have to make the most of what we have because I don't see a backline like the one we have coming around that often. Anything is possible with these players."
Ireland's forwards laid the foundations for victory against Italy, Wales and Scotland but it was a back who provided the sprinkling of stardust needed for Saturday's victory's at Twickenham.
Horgan rode a tackle from Lewis Moody and touched down with outstretched arms six minutes into injury time to condemn England to another fourth-place finish in the Six Nations.
"When you have backs like Brian O'Driscoll, Gordon D'Arcy and Geordan Murphy there are always tries that can be produced from nowhere," said O'Connell.
"In the end they scored down the blindside when Shaggy did unbelievably well. With players like that in the side anything can happen."
Ireland have now amassed three straight victories over the world champions and won their last two outings at Twickenham.
The rivals are heading in opposite directions - Eddie O'Sullivan's men can eye their summer tour with some confidence while shambolic England are backpedalling at a rate of knots.
Their ponderous backs were outclassed, although this had much to do with the painfully slow ball delivered to them, while up front their juggernaut pack failed to dominate.
"It was a very tough, physical game. England probably have the biggest pack we'll play against. But we defended well and communicated with each other," said O'Connell.
"The second half was a bit disappointing. Our defence was excellent but we didn't play as well as we did at times in the first half. It was a pity we didn't score more tries.
"We had made some good half breaks. We need to get over the line a bit more and that's something we must look at. We're still chasing an 80-minute performance.
"But winning tight games against top opposition was a big step forward for us. You need to win tight games - that's what good teams do. We've been close to it for years but now we're doing it.
"England are at their best with their backs to the wall. They've been brilliant at Twickenham and a lot of their players are very passionate guys.
"To go there and win against a team who were prepared to do anything and everything to succeed was a massive set-up for us."