Somewhere on the road between Auckland and Wellington this year, Warren Gatland had a Damascene moment.
The British and Irish Lions coach did something not many saw coming. After the Lions' first Test loss to the All Blacks at Eden Park, Gatland switched to dual playmakers for the next game at Westpac Stadium.
Out went Ben Te'o, who had performed admirably in the first Test but was thought by keen eyes to have butchered one overlap opportunity, and in came Johnny Sexton at No.10, nudging Owen Farrell to No.12.
The Lions never looked back and neither has Gatland. With an eye firmly on the 2019 World Cup, the coach has surrendered size in the Welsh midfield this weekend for guile. Jamie Roberts and Scott Williams, who were familiar to the Wallabies, are gone.
Owen Williams, who is a virtual stranger, is in.
Perhaps the Wallabies should hit-up Julian Salvi for some intel on the newcomer. Now of Gloucester, I first saw Williams play for Leicester alongside Salvi. He was a creative No.10, what you'd call a natural footballer.
Clearly Wales are going to try and move the ball with Williams at No.12. The romantics in Wales are intrigued by the potential, especially as the ambition doesn't end there.
Among the outside backs Gatland has gone for Steffan Evans. He would concede about 15 centimetres and 25 kilograms to the injured George North.
The lazy comparison to Evans would be Welsh legend Shane Williams, but I think he lacks Williams' top-end speed and see more of the Kiwi Nehe Milner-Skudder in him. The little wing/fullback is all about a low centre of gravity, footwork and changing direction at speed. We are in for some entertainment in Cardiff.
In some ways Wales are the most interesting team in the November internationals. No one else is attempting such a profound change of style. In some ways the old cliche about their performances meaning more than the results may be true. If the Welsh see some verve on attack a loss to the Wallabies wouldn't be a disaster.
A minor hammering would not be so well-received and say it quietly but it's not impossible. Some of the slickness and athletic prowess being shown by the Wallabies backline in recent games is frightening, in a good way.
Shaun Edwards made waves this week by saying the Wallabies attack in the first three phases was superior to the All Blacks. But it is true, until New Zealand can arrest their clunkiness between No.10 and No.12.
The key for Australia is to master the tactical approach Gatland has just abandoned. Samu Kerevi and Tevita Kuridrani are a terrifying prospect.
Yet my hunch is it's a selection misstep by the Wallabies. That's not a criticism of either player - they were terrific against Japan - but I struggle to think of a big man/big man midfield combination of the past 10-15 years that has worked.
Jean de Villiers and Jaque Fourie, perhaps, but they were footballers first, with their sizeable frames the icing on the cake. The appeal of Kerevi and Kuridrani is primarily power.
Clearly, Williams is going to be targeted but inside him at No.10 Dan Biggar is an excellent defender and will lend a hand.
It is elsewhere that the Wallabies could win the game.
In the back-row Taulupe Faletau is magnificent - among the 10 best players on the planet - but he is without three 2017 British and Irish Lions: Sam Warburton, Ross Moriarty and Justin Tipuric. Those are crippling omissions.
Tipuric may not have played in any of the Tests against the Lions but if he missed a tackle in any of the tour games I did not see it. As far as Warburton goes it will be his captaincy that is missed. Referees have time for him and he uses it smartly.
It adds to the Wallabies' advantage because the Welsh are notoriously slow starters at the beginning of their November campaigns. They are heading in an admirable new direction but Saturday might be too soon to see its benefits.