"You could point to a number of talented players in the last five or 10 years who do not fit the traditional mould. We've got guys who can hook, pull and cut that we've never had. The unfortunate thing is they're also getting out playing those shots.
"The stark truth is we don't have guys scoring hundreds; guys who can spend two days in the field and then go out and pile on runs themselves. To do that, you need to be mentally tough. You have to go back to Martin Crowe and Stephen Fleming to find guys who have done it in periods when we've done well.
"I'm not 100 per cent sure guys in this team understand that or have the mental fortitude. That's not to say they don't have the ability but right now, they're not doing it.
"It might just take one person, it might be that close. If one person stands up and does something incredible over a series of matches, things might start to turn around."
Taylor and Williamson showed the mettle Nash is talking about with their 262-run stand in the second test against Sri Lanka, a record for any New Zealand partnership there.
"Unfortunately, too often I see guys getting out slapping the ball to point and saying, 'That's how I play'. Sorry, that's not good enough," Nash says. "That's how you play and that's why you're averaging 35 and the best players in the world are averaging 55. Can you carry a couple of talented but flighty players? No, you can't.
"I'm not saying curb everybody's behaviour and turn them all into Mark Richardson. What I am saying is: ask more of every player. When you've got guys in the team who hide behind 'That's just how I play, take it or leave it', sorry, that's just pathetic.
"Honestly, if they added 10 per cent to their defensive game and a bit of thought as to how they construct their innings, they could be great players. We're asking you to execute better; use your head and develop your game. Those are things any sportsman worth his salt does."
Martin Crowe's open letter to the team on cricinfo.com ahead of the second test in Colombo is also worth a read for its instructive genius beyond the memorable line, "To bat six hours in a test is better than sex".
Crowe recommended that McCullum work on an impregnable defence; Guptill and Williamson shorten their backlifts to access the ball easier, particularly down the legside and Flynn play straighter rather than square. He suggested looking in the mirror rather than outside for answers to why they looked "dispirited, disjointed and disoriented"; success relied less on confidence than method and repetition.
Former coach David Trist says having watched the Sri Lankan series, Crowe's blueprint was a revelation.
"He explained what needed to be done and how to go about it, pure and simple. He needs to be working with members of this team. He talked about the need for concentration, determination, wearing down the opposition bowling attack so you can go to work on them.
"I remember a tour to Australia where he worked with the likes of Scott Styris, Mark Richardson and Jake Oram at their request. The only minor issue is that when he watches matches, he struggles to understand why they don't pick up concepts as quickly as he can. But that's genius for you."
