Sexton earned 124 Test caps in his career, 118 for Ireland and six more for the British and Irish Lions.
World Player of the Year in 2018, he would win five Six Nations titles, three of them Grand Slams, but that defeat to New Zealand was a fourth World Cup campaign where he could not help Ireland beyond the last eight.
In what is his second autobiography, he states he still believes Andy Farrell’s men were the best team at the tournament last year.
“I know I’m biased. And I know that South Africans – and others – will tell me to look in the record books. But it wouldn’t be the first time that the best side in a sports tournament didn’t end up winning it.”
Ireland have reached the quarter-finals eight times in World Cup history, losing on all eight occasions, with the most recent two of those defeats coming against the All Blacks.
Sexton does not feel the poor record played any part in last year’s loss.
“People have asked me if we were nervous before the quarter-final, if we felt the weight of history on our shoulders, if we did anything differently from previous games,” he says.
“Yes, we were nervous, but no more so than before any other game. Revisit the first couple of minutes and it’s the All Blacks who look incredibly jittery. I don’t believe history had any relevance.
“We just didn’t play to our optimum, or even at 90% capability.”
Ireland will face New Zealand for the first time since the World Cup in November.
BBC Sport has approached New Zealand Rugby and Rieko Ioane’s representatives for comment.
