A gigantic effort has been made, at home before they left for the World Cup and here in South Africa, to change the stereotype, so much so that it can no longer be said to be true. But even so, as the All Blacks prepare for Sunday's semi-final against England in Cape Town the pressure is affecting them more than they might wish.
It is not to their discredit that this should be so, but after what has seemed to be a million interviews in the month since their arrival efforts are being made to protect the boy wonder, to keep him from the limelight in which he has been bathed by his own outstanding performances.
In fact, New Zealand's outside-half sensation could not have been more patient, polite or comfortable as he conducted himself with a maturity way beyond his 22 years in a quiet corner of the All Blacks' Pretoria hotel yesterday. Talking or playing, running or kicking, this guy is an absolute natural.
As he does not look 22, it would be no surprise to find that he had amassed all of four caps were it not for the bravura of his performances in this World Cup. Sixty points in the matches against Ireland, Wales and Scotland to add to the 28 he scored in his first Test, against Canada in April, are the bald statistics of a burgeoning career.
"It hasn't been the hardest job to settle in," Mehrtens (the surname is German) said. "I haven't really been exposed to a heck of a lot yet because our forwards have dominated, if not completely and right the way through then for most of it, every Test I've played.
"So far I haven't had a baptism of fire. Every game has got a bit harder as the tournament has gone along and the semi-final against England will obviously be the hardest yet. So I've been pretty lucky."
That is one way of putting it, but you could equally argue that here is a natural talent which has found its natural level. New Zealand have been searching since 1993 for a successor to the prolific points-gatherer and tactical master, Grant Fox, and here at last - Walter Little, Jon Preston, Simon Mannix, Stephen Bachop and Marc Ellis having been and gone - he is.
Not that the Fox legacy burdens Mehrtens. "Whoever is playing first-five, whoever succeeded Grant Fox, you are simply picked for the All Blacks and not to try to play like anyone else," he said. "The All Blacks have been criticised for boring rugby but this year the selectors have encouraged me - like everyone else - to play my natural game. I have no responsibility to be like Grant Fox; the only responsibility I have is to go out and do my best."
Mehrtens may not yet have Fox's phenomenal accuracy as a place-kicker or punter but in four Tests he has already brought more variety and less predictability to New Zealand's play than his vaunted predecessor did in 46. Consider how he ran 70 yards for his breathtaking try in last Sunday's quarter-final against Scotland at Loftus Versfeld, the colt accelerating like a thoroughbred beyond the reach of the bemused Gavin Hastings.
This was his finest moment as an international, yet Mehrtens greets it only with an agreeable self-deprecation. "I was embarrassed to watch it afterwards because I thought I looked like a frightened rabbit. Gavin maybe didn't expect me to have the confidence or audacity to run outside him but I wasn't really thinking about it and I wouldn't make out it was planned all along.
"It was more my wonky running style that caught them unawares. They seem to be the tries I get, out of the blue, a wee bit opportunistic, and I always end up making a clumsy attempt to dive and falling flat on my gut."
The South Africans have been especially interested in him since they discovered that he was born in Durban. His parents enjoyed a holiday in Natal so much that they stayed for five years from 1969, his father playing for the provincial side against the All Blacks in 1970 having played for New Zealand Under-21 against the Springboks in 1965.
He also played for his native Canterbury and in 1974 the family - Andrew aged 18 months - returned home to Christchurch, where Terry Mehrtens is a primary-school headmaster. Mehrtens Jnr made his provincial debut in 1993, when he was on the bench for Canterbury's game against the Lions at Lancaster Park, but was initially chosen at full-back and became the regular outside-half only last year.
So it is not in 1995 that things have come in a rush, though his studies as a history undergraduate have been so slow that he is now into his fifth year at the University of Christchurch. Ask him if he quite believes it, whether he would wake up if he were to blink, and he answers: "I haven't even had time to blink."
England may be about to make him flicker his eyelids, but there is no suggestion from his composed demeanour that he would treat adversity any differently from triumph. "It really hasn't sunk in yet," Mehrtens said. "The only time I got excited was when I came home after the team had been named and saw how happy my father was.
"It's still early days for me but you can't assess experience only from the number of games you play. Someone who has played 10 might have learned as much as someone who's played 60. It's what you learn that counts and although I've learned a lot I have a hell of a lot more to learn." He could not have put it better. This is one All Black who is also pure gold.Reuse content