I can't recall a more talked-about Tri Nations rugby tournament than the one that's about to conclude with an epic contest in Brisbane on Saturday night when the All Blacks and Wallabies square off for the southern hemisphere crown and the Bledisloe Cup.

There's been plenty of talk about rugby's problems over the past few years, including claims that the Tri Nations is boring and too much of the same-old, same-old. In the past I've advocated they play it every second year, the years before and after a world cup, with a major tour in the middle year. 

Despite that kind of talk, TV ratings and crowds have always been good and the Tri Nations has always seemed to be popular. And this year's tournament will only help boost the popularity.

This has been a bizarre tournament if only for the huge turnaround in results from one game to the next.

It started with two high-quality games between New Zealand and South Africa. We won with a degree of comfort in Wellington and they won a tight contest in Dunedin before losing to Australia in Perth.

We then got belted in Sydney before reversing that a week later by thumping the Wallabies at Eden Park in one of the biggest turnarounds you're likely to see in a trans-Tasman clash.

Most pundits thought that once South Africa got home they'd be odds-on to win the Tri Nations. They got sufficient points on the road and are difficult to beat in their own backyard. I don't think too many people would have predicted they would lose comprehensively to us in Cape Town and go down easily to Australia in Durban.

With their season turning to rubbish they then destroyed Australia with a half-century hiding in Johannesburg.

I believe the over-riding reason for these turnarounds is mental toughness. Mental strength plays a significant role in elite sport. In team sports you will see sides who appear to evenly matched on paper, but one of them scores a blow-out win because the losing side isn't right up for it mentally. That's what we've witnessed in this Tri Nations.

I'll come back to this point in a moment, but indulge me in a diversion on the Experimental Law Variations.

During the week, All Blacks centre Conrad Smith said the ELVs made it easier for a team to score a blowout win if they could get early dominance and build momentum.

I'm not totally sure I agree with that in its entirety, but one thing the ELVs do allow is for a team to get on the front foot, and stay there for a periods of time. The main reason for this is the rule which has the defending team back 5m at scrum time. That makes it easier for the attacking side to get to the advantage line and we know that getting over the advantage line is critical. So from a scrum it is easier to create that initial momentum and thus build pressure.

Another area the ELVs have effected the game is in the lack of quality counter-attacking, which is not as good as it used to be.

That's symptomatic of ELVs at breakdown. Players now fear being isolated and therefore giving up a free kick in their own half. The side that gets the free kick can take a scrum and build attacking momentum. A side can also gain that advantage with an astute kick-and-chase, isolating the ball carrier, which is why we've seen more kicking under these ELVs.

Let's get back to mental toughness. For those first two games in New Zealand, the Springboks were in reasonable shape mentally, but they started to struggle once they got to the third week on the road in Perth against an Aussie side that was up for it in their Tri-Nations opener.

For some reason we weren't quite right for the game in Sydney and I've never really put my finger on it until a former colleague, who shall remain nameless, came up with an interesting theory. His observation was that even though the coaching staff on both sides were playing down the fact, the game was the first "head-to-head" between Graham Henry and Robbie Deans, and it would have been impossible for either coach not to feel the pressure, given how much context was involved in the clash.

My colleague's view is that perhaps the All Blacks' coaches were actually feeling the pressure more than they admitted and that was transferred to the team, resulting in an uncharacteristic nervous, error-ridden performance.

The more I thought about it, the more merit it seemed to have.

After that loss, the All Blacks responded as they traditionally do and our attitude was A1 in Auckland while Australia, playing for the third week in a row, weren't quite there.

In Cape Town, both the All Blacks and Boks were up for it, but the All Blacks were better. Ditto in Durban when Australia beat South Africa. But at Jo'burg, the Boks, stung by two losses in row at home, were fierce.

In Brisbane next week I believe both teams will be "in the house" big time. I can't see it any other way.

In that respect I don't see the mental factor being in play.

What has been evident for me when and I look at the games at Eden Park and Ellis Park is the Australians were physically dominated in both those games and therefore they struggled. In both of those games, Australia allowed themselves to be "beaten up" because they weren't quite there mentally.

Because they will be fired up for the Battle of Brisbane it may not be so easy for the All Blacks to get the physical dominance they need to beat Australia.

I don't think there will be much in it, but the All Blacks will win a close one.