Every man had his breaking point, D'Arcy wrote in his column in The Irish Times.
"If the whistle of Nigel Owens – one of several leading males in the epic tale that is about to unfold – shrills on 80 minutes with big fat zeros beside the names of Beauden Barrett and Ardie Savea when it comes to offloading and line breaks then victory will belong to Ireland," he said.
D'Arcy never tasted victory against the All Blacks, but was part of the injury time loss suffered in Dublin in 2013 when second five-eighths Ryan Crotty scored to level the scores and allow first five-eighths Aaron Cruden his double attempt at the final conversion.
"I remember 2013 like it was last week. The agony of that loss will never fade but I know the hurt fuelled the boys who carried the torch to Chicago. I could feel how that victory brought our national rugby team to the majestic heights of last November's titanic win in Dublin," he said.
Beating New Zealand was an enormous feat and only France, South Africa and Australia had managed it at World Cup level. Each defeat suffered had been games for the ages, he said.
D'Arcy acknowledged Ireland's wins over the All Blacks could have resulted in New Zealand excuses – in Chicago they were without locks Brodie Retallick and Sam Whitelock and in Dublin last year they had come off a tough game against England a week earlier and were at the end of a long season.
But the All Blacks didn't usually opt for excuses, they went for revenge, he said.
"That's not to take away from two brilliant Irish performances.
"I'm just saying this is a World Cup quarterfinal. I am just writing with the memory of those scintillating double blows the All Blacks inflicted on the mighty Springboks not a month ago. I am also saying we have a chance. Nothing more, nothing less," he said.
D'Arcy said Ireland would need to repeat their previous examples of discipline, defensive standards and concentration levels.
Ireland's win over Samoa at the weekend had not been enough to make D'Arcy confident in the side, nor was the side's last 11 months.
"This is Ireland's World Cup final…What needs to happen is Ireland must frustrate the hell out of New Zealand, imprint the word 'Ireland' in their psyche forever more, and that starts in the same place they hurt them in Chicago. [Locks] Iain Henderson and James Ryan need to overshadow Retallick and Whitelock. They must overpower two of the biggest and most powerful men to ever wear the black jersey.
"They need to disrupt the lineout and deliver a flawless Irish set piece that yields tries via the maul," he said.
Ireland needed to beat the All Blacks up front because that was where they were always beaten, along with zero missed tackles and single figure penalty counts.
"Win it playing Schmidt's rugby. Starve them of possession. That is the only way," D'Arcy said.