The full extent of Carter's knee issue was only revealed by Ian Foster after the final. Foster said: "He tweaked his knee in the last few minutes of the French game and it was looking a little bit touch and go for South Africa. But he really came through in the latter part of that training week really well so those doubts were point to bed very quickly.
Really, he's been someone who hasn't been able to train fully at 100 per cent all week.
"It was his decision to play with strapping. I think he could have played without it, but it probably gave him that extra one per cent that he needed and it probably turned out to be quite helpful."
Another World Cup ruined by injury would have been too cruel for words. Instead, he will go to Racing Metro as a genuine World Cup winner, the darkness of his experience four years ago lending greater light to this one.
Straight after the game, Carter said of his feelings leading up to the most important game of his considerable career: "I've been fighting those thoughts all week - those thoughts about the outcome and whether we were going to win or whether we were going to lose ...
"I just kept pulling myself back to process and concentrate on the task at hand for the 80 minutes. But once that final whistle went - it was a great opportunity to release the emotions. I'm just so proud."
"It's ahead of anything else that I've achieved in the black jersey," he said. "It's such a special night. to be a part of such a special group and to achieve something that no one else has done - to, I guess, finish my career on such a high. It's a dream come true."
No one, probably not even the most fervent of Australian supporters, will begrudge him this. Fairytales don't come along too often in the unforgiving business of professional sport, and few could have foreseen this even earlier this year as he struggled on his return from yet another leg injury and couldn't dislodge Slade from the Crusaders' No10 jersey.
His mate in the No12 jersey, Ma'a Nonu, knows Carter better than most. Asked whether he was confident his long-range dropped goal attempt in the final would go over, Nonu said: "I'll back DC any day, really. It's a matter of him backing himself. He's thrived on the last three weeks, really, with self confidence. He really wanted to have a good World Cup for himself, and I think he did that."
Foster added in the aftermath of the win: "I think we saw last week he really hit some peak form and I think he continued that tonight. He's been in the groove probably through most of this tournament. You could see him just building and building.
"When we needed him to step up and make some decisions and go out on a bit of a limb and have a crack at a drop kick again he did it - just like last week. He followed it up with a big, long penalty which was at a pretty important stage as well. He should be pretty satisfied with what he has done. He has left this team in a pretty good space. He's guided it well and done himself proud."
There was the merest hint of McCaw's foot injury of 2011 in Carter's knee problem. While it wasn't anywhere near as serious or painful as his skipper's, it would have taken mental strength and self belief to block out before the two biggest games of his life. It was a reminder, too, that the biggest prizes are worth fighting for.
Job done, dream realised.
- By Patrick McKendry in London