All Black Aaron Cruden tips long-time coach Dave Rennie for 'great things' at Glasgow

Dave Rennie has coached All Black fly-half Aaron Cruden at three different teams

Rugby World Cup-winning All Black Aaron Cruden says in long-time mentor Dave Rennie, Glasgow Warriors have one of the world's best coaches.

With Cruden at fly-half, Rennie guided the Chiefs to two Super Rugby titles in their native New Zealand.

He leads Warriors into their maiden Pro14 campaign on Saturday.

"He's very diligent, works really hard behind the scenes, and he's got a really positive mind-set in the way he likes rugby to be played," Cruden says.

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"I think he will be coaching at international level in future. I know he's really looking forward to this new challenge and he's going to do great things [at Glasgow] as well. I'm not sure who the next All Blacks coach will be, but if it was Dave Rennie, he would do a fantastic job."

Their association stretches back almost a decade, when Cruden was Rennie's New Zealand Under-20 captain, then his youthful pivot at the Manawatu Turbos in New Zealand's domestic ITM Cup.

Rennie arrived in Glasgow in August after six seasons at the Chiefs

As Cruden talks about Rennie, the superlatives cascade forth like the Waikato River, the waterway that flows through the heart of Chiefs country.

He sees things others don't - or can't. He harvests raw talent and adds value and polish. He sculpts "winnings cultures", driving the importance of unity, brotherhood and belonging, and surrounds himself with "good men".

'He made me think differently'

"It was just the perfect style of coach that fit with the type of player I wanted to become," Cruden, 28, told BBC Scotland.

"He absolutely respects the set-piece, because without gaining dominance up front you can't really do much, but he has the ability to see things a little differently from other coaches.

"I really liked the way he was able to develop each player and understand what they needed to work on or continued to do to strengthen their skills.

Cruden was Rennie's captain as he led New Zealand Under-20 to three straight Junior World Championship titles

"He puts time into his players; it's all about the little skills and the little details, so that when you are under pressure out on the field, it's just second nature.

"Rens was always able to challenge me in a way that would make me think about things differently on the field.

"He's always prepared to evolve and develop, and keep the initiative so that you don't get stale or stuck in thinking there's only one way to do things on the rugby field."

'Playing for more than yourself'

When Rennie took charge five years ago, the Chiefs had only reached the knockout rounds of Super Rugby twice since the tournament's inception in 1996.

Yet, with canny recruitment and clever man-management, Rennie piloted them to back-to-back titles in his first two seasons.

Rennie was the first head coach since 2000 to win a Super Rugby title in his maiden season

"He was just always able, regardless of what team it was and what personnel he had, to create good habits and winning cultures," Cruden, who has won 50 New Zealand caps, says.

"When you are able to produce that sort of culture, it just gains momentum every time you go out there and train or play.

"I think that is because he really cares about his players - he gets to know them as people as well as rugby players, and when you've got a coach like that, you just feel really secure in the fact you know you're going out there for more than just yourself.

"He didn't see the [previous lack of success] as a problem, he saw it more as an opportunity. I remember him constantly talking about that in those first few years - we have an opportunity to do something no other Chiefs team has done before.

During Rennie's six-year stint in charge, 12 Chiefs players made their New Zealand debuts

"When you're starting to talk like that, change your behaviours into good habits, all that stuff provides momentum. Once you capture that momentum and run with it, it just seems to get more powerful."

'He's extremely approachable'

Those in the Warriors camp have already spoken about Rennie's "family-orientated" ethos, and the importance of a team immersing itself among the people it represents.

"Regardless of whether I was playing with another team, Rens would always say to me if there was anything I wanted to talk to him about, or wanted a different perspective on, I was always able to approach him," Cruden, a member of New Zealand's 2011 World Cup-winning squad, says.

"It's his qualities as a person off the field as well. He's extremely approachable, he is big on making things a real family environment. That was something I admired about him immensely.

Cruden has 50 All Blacks caps to his name, featuring in each of their Tests against the British and Irish Lions

"Rens has always had a nice way about being able to be firm when he has to, but when there's an opportunity to be a bit more personal, get to know guys, relax and not even talk about rugby, he's able to do that as well. I think that's a real skill to have as a person."

Cruden, like Rennie, has left the Chiefs, taking up a lucrative three-year contract with Vern Cotter's Montpellier.

His mentor had floated the idea of continuing their journey together in Glasgow, but as fate would have it, their new teams lock horns in December in their European Champions Cup pool.

'He did mention coming to Glasgow'

"He did mention [coming to Glasgow] to me. He said, maybe I could come along after we've had a stint in France - come home via Glasgow," he says.

"You never say never. Rugby is such a beautiful game, it creates so many wonderful opportunities for people, you never know where you can end up.

Scotland Under-20 fly-half Adam Hastings is one of Rennie's 11 summer signings

"We were laughing about [the European draw] before we moved over. That's going to be a little bit of fun, it'll be nice to come up against Rens in a different format, and hopefully enjoy each other's company after the game."