If that had all the makings of a Tui billboard, his next intervention rang more true. There was a thought that New Zealand's relatively easy passage through Pool A had left a few boxes unchecked, particularly the middle-order batting, but Vettori put the doubters in their place by saying box-ticking was nothing more than a media construct and that all they were worried about was winning.
He may no longer be a neon-lit cricketer, but he is the glue that holds this potent attack together. If one of the seamers is having an off day (as Southee did against Australia), throw Vettori on early.
Hold the score in check during the middle overs, Vettori is your man. There's a Williamson T-shirt doing the rounds that says "Steady the Ship", and it could equally apply to Vettori at the bowling crease.
"It's the experience he's been able to build over a long period of time," says McCullum. "The physique of the guy has changed a lot - so has the beard and the back hair. His development as a cricketer throughout his career has been phenomenal.
"He's referred to as a bit of a wizard, too, from the teams in Australia and his art and ability to read a game, use a change of pace, is something not too many other guys around the world have.
"A couple of years ago he was struggling for fitness and what we've seen is a guy who has gone away and worked incredibly hard, and to still have that inner drive to be part of a New Zealand team and give himself a chance to achieve something special."
That he has 12 wickets already, just one behind Southee and Boult and one ahead of next best spinner Ravi Ashwin, is something of a bonus to McCullum. Vettori has not been a renowned wicket-taker for some time. He is the guy the opposition have been content to milk for a low-risk four an over, while targeting the guy at the other end.
To highlight Vettori's continuing pre-eminence as a finger spinner, we have looked at every ball he has delivered at the World Cup, looking not just at the value of the outcome but also what the batsman was trying to achieve.
This has been divided into three modes: defence, attack and working. These are subjective categories that are not necessarily outcome-based, but still give a picture of how difficult batsmen, even in these run-friendly conditions, find it to "get" to Vettori.
Defence is when a batsman is not trying to score a run. They are simply trying to keep it out and move on to the next ball. On occasions, runs might be scored, with a squirted inside or outside edge eluding the keeper, but for all intents and purposes, the batsman was not attempting to score.
Attack is a category for boundary hitting. To be regarded as an attacking shot in this context, the batsman must be trying to reach the rope. It still might be a dot ball - there were several attacking shots by Australians that found fielders inside the circle - but the intent was clear.
The third category is when the batsman is looking to work the ball into a gap for a single. There are three main shots here: the push down the ground to long on or long off; the working off the legs into gaps on the onside; or trying to work the ball out through point or cover to the offside sweeper. Some are arguable, like whether a sweep is trying to access the boundary or is simply turning over strike, but for the purposes of this exercise a slog sweep is "attack", a paddle-sweep is "working".
What stands out is that even though batsmen know they need to be more positive against Vettori, they still struggle to find balls they can attack. Of the legal deliveries he's bowled, batsmen have only tried to find the boundary 11.8 per cent of the time. Compare that to 36 per cent of his deliveries where the strikers have not attempted to score at all and it tells of a bowler at the top of his craft.
So, do any of his teammates get to him in the nets? "I've tried a couple of times but it hasn't really worked," McCullum says. "Not many guys are able to get on top of him. He's got that ability to chop and change his pace and make you look a bit silly. So you just try to get down the other end."
With Rangana Herath more of a test specialist, the next best left-arm spinners at the World Cup are Bangladesh's Shakib-al-Hasan and India's Ravi Jadeja. Look at their overall figures compared to Vettori's.
Vettori: 45.2-5-136-12
Al-Hasan: 38.5-0-185-3
Jadeja: 38.4-0-188-7
They have both been useful, but not Vettori-esque. Jadeja's 125 dot balls represent 53.9 per cent of the 232 deliveries he has bowled, while Shakib has managed 119 dot balls, 51.1 per cent of his total. Of Vettori's legal deliveries, 62.2 per cent of them are dots.
When teams are setting their sights on 350 and beyond, Vettori's efforts can be summed up in two words - casual brilliance.
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