The All Blacks had played under intense pressure for six weeks - they lost injured fly-halves Dan Carter, Aaron Cruden and Colin Slade along the way - but somehow prevailed 8-7 against fired-up France.
Les Bleus set the tone before kick-off, marching on New Zealand's traditional pre-match haka. By transgressing across the halfway line, France are likely to be hit with a £10,000 fine from World Cup organisers.
But money could not buy the gesture - and intensity of France's subsequent challenge - as they pushed New Zealand to the limit with a performance that belied their miserable pre-final form.
Relief was etched deep into the faces of McCaw, All Blacks supremo Graham Henry and his coaching colleagues Steve Hansen and Wayne Smith, before victory was secured by two unlikely heroes - prop Tony Woodcock and substitute Stephen Donald.
Woodcock scored the All Blacks try, while new Bath signing Donald's second-half penalty tilted the contest. Two weeks earlier he had been whitebait fishing on the Waikato River when he was summoned as squad replacement for an injured Colin Slade.
The All Blacks squad will now begin three days of public celebration, starting with an open-top bus tour through central Auckland tomorrow, but it could - and perhaps should - have been a different story.
"It wasn't very pretty, but it came down to how much desire, how much courage the boys had," McCaw said.
"A lot of guys have put a lot of effort in for a long time, and they weren't going to let the opportunity go.
"We probably didn't play our best, but we played good enough. I take my hat off to every single player who took to the field."
Thierry Dusautoir's converted try brought France to within a point of the tournament hosts, and McCaw said: "The big thing was not panicking.
"We had talked about being in situations like that for a few years, and what we would do in those situations.
"You have got to keep the belief and trust. We had to dig pretty deep, but the last thing we wanted to do was panic. We managed to hang in there.
"We know we were going to be in for a hell of a game. We realised that all week. You couldn't get much tougher than it was today.
"The guys stuck to their guns, and we got there."
As for France's approach to the haka, McCaw added: "We talked about them bringing something different, and they did, but the game doesn't start until the whistle blows, does it.
"If anything, it showed us what we were in for, and that was exactly what we got. They were right up for the game, as we expected, and they certainly made it tough."
An emotional Henry will now step down as All Blacks chief - Hansen is favourite to take over - and he paid a glowing tribute to his players and support staff who made the country's first World Cup triumph since 1987 possible.
"Personally, you've got some peace, and that's a great feeling," Henry said. "This thing was about winning, and the guys have won the World Cup. That is outstanding.
"We have been through a lot together. A lot of the guys played in the last World Cup and fell at the quarter-final (against France), and to win this, there are no words for it, quite frankly.
"We were under a lot of pressure. France gave very few penalties away, their defence was very strong and we gutsed it out. I think that shows some mental strength.
"This team has been ranked number one in the world for a long time, and it is just great to be able to hang in there and do the business and under real pressure.
"The French played particularly well for long periods of that game and controlled the ball. To play in those situations and hang in there and come through with a win is something we wouldn't have done perhaps two or three years ago."
Henry reflected on the New Zealand Rugby Union's decision to reappoint him in 2007 after the pain of a quarter-final loss against France at the Millennium Stadium.
His bosses could easily have dispensed with him - New Zealander and current Australia coach Robbie Deans was favourite for the job - but that faith was justified today.
Henry added: "People make decisions, and I was lucky enough to be reappointed. I just feel really thankful to the guys who reappointed this group of people.
"I think far too much time in sport people are replaced because they don't get the right result, and quite often they're very good at what they do.
"I am not saying I am, but quite often they are, and they just need another chance and then you get good results.
"Look at some of the coaches around the world. They're pretty mature people.
"We are probably too quick to shoot the coach because a team hasn't produced at the World Cup previously or got a big result.
"What the New Zealand RU did in 2007 was a difficult thing for them to do, but maybe it was the right thing to do. Maybe we've learned from that.
"I wasn't going to re-stand after 2007. But from the reaction of the players, they wanted the current coaching panel to continue. That is why I re-stood.
"We put a lot of pressure on the players to perform week in and week out in Test matches. This was our 12th Test match in 14 weeks, and there are big demands made by the three of us for Richie and his team to perform.
"Part of the deal is you've got to hang in there because those are the situations that you learn from. I learned more from the 2001 Lions tour (when Henry was head coach) than anything I'd been involved in.
"That is the beauty of continuity that people continue to be involved, rather than a wholesale clean-out and start again. How do you learn from that?"
Asked, though, if he might now fancy the England job following the 2003 world champions' wretched campaign in New Zealand, Henry replied: "I think that would be a divorce.
"I will just enjoy today, I think, and the next few days."
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