Australia end losing streak against ABs
O'Connor's nerveless kick minutes after the siren sounded also brought an end to New Zealand's 15-Test winning sequence and will send the Australians off on their forthcoming European tour brimming with confidence.
"I still can't believe it, it's a pretty surreal moment," O'Connor said after being mobbed by elated team-mates.
"They're the things that you dream about when you're a kid... it's a dream come true."
Australia looked to have blown their chance of beating the All Blacks for the first time since 2008 when their early lead was snuffed out in front of a disappointingly low crowd at the Hong Kong Stadium.
The Wallabies grabbed a 12-0 advantage through a try from fly-half Quade Cooper and a brilliant solo effort from Adam Ashley-Cooper, who smashed through the All Blacks centres at halfway and dummied Cory Jane to touch down under the posts.
New Zealand kept their composure, however, and converted tries from scrum-half Jimmy Cowan and winger Jane had them back in front after 33 minutes before fly-half Dan Carter, back after injury, added a penalty to put them 17-12 ahead at the break.
The Tri-Nations champions, who had already secured the Bledisloe Cup, further extended their lead with a typically clinical try from centre Ma'a Nonu after 54 minutes.
Australia, who lost 23-22 in their last Test against New Zealand, were not yet beaten and Drew Mitchell powered down the line to score in the corner after Kurtley Beale broke when Conrad Smith lost his footing just past the hour mark.
Mitchell's score left the Wallabies needing a converted try to win and, after Carter's replacement Stephen Donald had missed a penalty which would have sealed victory for the All Blacks, Australia laid siege to the New Zealand line.
The Australians showed great patience and discipline through several phases of play before O'Connor cut between two defenders and touched down to tie the scores, giving him his chance of a kick for glory.
New Zealand, now deprived of the chance of exceeding Lithuania's record of 18 consecutive Test wins, also head for Europe next for a tour of Britain and Ireland.
"It was disappointing, we had a chance to close out the game but they put us under pressure and we didn't manage to do it," said skipper Richie McCaw.
"It was just one of those days (but) when you have a bad day at the office you just have to get straight back on the horse."