Justin Marshall's chalkboard: How Wales can trouble the All Blacks

George North (L) of the Wales celebrating his team scoring during the test match between New Zealand All Blacks and Wales. Photo / Getty Images.

It will be interesting to see what Wales have to offer in Wellington after what I thought was an excellent performance on attack, but I'm also very keen on seeing what they do on defence.

I believe they did a very good job at Eden Park last weekend in one particular area, an area that Wales have adopted in the last four or five years under Warren Gatland in association with his defence coach Shaun Edwards, who has a background in rugby league.

And that is their out-to-in defence. Traditionally teams have defended from the inside out, which means they push the attacking team across the field towards the touchline.

But an outside-in, or 'umbrella' defence, cuts off the attack from the outside.

I noticed last weekend that the All Blacks were able to get overlaps through good ruck ball - perhaps three attackers on one defender - but weren't able to make the most of them, not because the inside defenders were shutting them down, but because midfielder Jamie Roberts, a smart player and one of the best in Europe, recognised the threat and went up on his own. It wasn't so much part of a pattern, more a one-man blitz defence as he raced up and got in the eye-line of those with the ball.

Even though he might not have made a tackle, he's there with his size and really stands out. With test rugby being so quick, even though you are hearing voices from the outside, you can see that big red jersey in your peripheral vision and it makes it difficult to get the ball there.

What's the solution? The first receiver must get rid of the ball quicker and the other players must recognise that Roberts or one of his teammates has raced up and left a huge hole in the defensive line. Rather than hold their width, the All Blacks must be pro-active and hit that space.

I'm sure they've seen it in the review - certainly, defence coach Wayne Smith would have.

For me it's fascinating because it brings an element of chess to the test; move and counter move. Wales will be aware that the All Blacks know it, but will probably continue to do it because they have to stop leaking points. I can't wait to see the outcome.