A titanic quarter-final at Wellington Regional Stadium ended with Wales emerging from a compelling contest worthy 22-10 winners.
In public Ireland's mantra throughout their stay in New Zealand was to never look beyond the next match, but Best has revealed that privately they were intent on lifting the Webb Ellis trophy.
Routing Australia en route to finishing pool winners to reach the all-RBS 6 Nations half of the quarter-final draw only strengthened their conviction 2011 was to be their time.
In an honest assessment of their agonising demise in the tournament, Best insists they will take no solace in the special memories they have given to the hordes of supporters who followed them across New Zealand.
"It will take a while to get over this. There's no doubt that this was a fantastic chance, we all knew it," said the Ulster hooker.
"We all knew that topping our group would put us in a north-south hemisphere split and turn it into knockout Six Nations rugby.
"We knew we had the ability to win that side of the draw, but we also knew we had to turn up on the day.
"Once we get home and when we're in the cold light of day, we'll reflect on some fantastic moments.
"There was the atmosphere at Auckland Park and Otago Stadium. The support we've had has been great.
"But the bottom line is that we travelled to New Zealand to win the World Cup.
"We didn't talk a whole lot about it, but that was our ambition.
"We knew deep down that we hadn't really performed on the big stage before and this was the time to do it.
"We got to the quarter-final confident that we could win, but failed to achieve that.
"Any time you get to that stage of a competition it's always an opportunity missed, unless you get to the final and win it."
To be critical of a team that contributed so fully to a remarkable quarter-final between two of the World Cup's form sides would be grossly unfair.
When the time came, Ireland fell agonisingly short to magnificent opponents who displayed a level of maturity and composure that belied their lack of experience.
Ranks full of seasoned campaigners steeped in the knowledge of how to win cup games, it was meant to be the hard-nosed Irish who delivered at critical moments.
Instead, confronted by a ferocious defence, they failed to convert pressure into points in their most error-strewn performance of the World Cup topped by some weak tackling.
"We're bitterly disappointed. Credit to Wales, but for us the emotion is very raw. It's just one of those things unfortunately," he said.
"It's a team game and we're all in this together. We've had a fantastic time in New Zealand.
"There's been a great feeling throughout the squad while we've been here and we're all very disappointed to be going home.
"We came up short here. We wanted to get into the last four. It was something we wanted badly, but we haven't managed it."
Instead, it is Wales who progress to the last four with France blocking their path to a first World Cup final appearance.
Best believes Warren Gatland's side have all the tools to progress to the showpiece at Eden Park on October 23.
"Credit to Wales, they came at us and didn't let us settle or gather breath. They were deserving winners," he said.
"Good luck to Wales next weekend, they thoroughly deserve to be there. We can have no complaints.
"There's no doubt Wales can reach the final. The beauty of this side of the draw is that it's very much the Six Nations.
"Wales have shown in the recent past that they can win Grand Slams. That's basically what they have to do now to get to the final."
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