And while all five tries came from backs - wingers Sitiveni Sivivatu and Doug Howlett both crossed twice and scrum-half Piri Weepu added the fifth - O'Kelly insists it was the tourists' power up front that ultimately decided the outcome of Saturday's 45-7 success.
"We didn't get any possession in the first half and they were 20 points up before we had any real opportunity to score," said O'Kelly.
"When they're that far ahead they can play glamorous rugby and when that happens we're in trouble. By half-time it was all over and after that it was a case of trying to give a performance worthy of an Irish team.
"We stood up in the second half and started pushing things and eventually the try came with Marcus Horan going over. The lads deserved it.
"New Zealand were more physical than we were. They are really big guys and big ball carriers who can offload and run the right lines.
"They're used to breaking tackles and then giving off passes. Physically they're bigger than us.
"But they're not just stronger - every one of their players is dangerous and can score tries from anywhere so we were chasing shadows at times.
"They used a mixture of first and second-string players but still gave us a serious lesson.
"They're a young side but I think the Pacific Islanders mature quicker than the Irish. They're looking good for the World Cup at this stage."