In a truly breathtaking encounter at the Aviva Stadium, O'Connell saw his side surrender a 22-17 lead when 80 minutes were already up on the clock.
But Ryan Crotty went over in time added on, Aaron Cruden added a retaken conversion and before a disbelieving Dublin crowd the Kiwis had emerged 24-22 victors.
O'Connell and co. showed great heart to bounce back from their Australian mauling of the week before and raced into a 19-0 lead on Sunday, at which stage a first-ever Irish win over New Zealand looked very much on the cards.
But not for nothing are the All Blacks, who the Lions will be touring against in 2017, the best side in world rugby and their comeback means Ireland must learn their lessons.
"It's obviously very important we build on it," he said.
"We have produced these big performances full of accuracy in the past and we haven't followed it up.
"The onus is on the players to maintain that standard.
"The next few weeks is a bit of distraction, with big games in the Heineken Cup, the inter-provincial derbies, and that, but it's important to keep this in the back of our minds as a marker."