Justin Marshall's Chalkboard: Cooper the key

Red playmaker Quade Cooper will be fired up against the Blues today, earning his 100th cap. Photo / Getty Images

The Chiefs have a big challenge ahead of them tomorrow night, with recent losses making their place in the playoffs more precarious than they would have liked.

Going to Brisbane and playing the Reds six weeks ago, you could have almost guaranteed banking four points. But now that they have an abundance of players back, including the mercurial Quade Cooper, they're a different beast. They're actually a formidable opponent now.

It's a must-win game for the Chiefs, and Cooper is one of the key players they need to shut down. He was instrumental in the Reds beating the Force last week and, if the Chiefs let him have free reign tomorrow night, he could again be the decisive player on the field.

What Quade Cooper wants to do is square up defenders. When he has defenders coming at him, he wants to have them square onto him, as you can see in the first diagram about the bad way to defend him.

Cooper has very good footwork and, if players get too square, it gives him the ability to manipulate the defender either on the inside or on the outside. He's looking for two things - to beat the player or, if he can't beat him, the ability to find a weak shoulder and use his brilliant offload game.

That's when he's at his most dangerous and, when he squares up a defender, it also has a massive impact on the player on either side on that defender, because they have to turn in or turn out and it takes an extra player out of the defensive pattern.

So the good way to defend against Cooper is to give him only one option and shut down the inside channel. The defenders need to exaggerate the inside shoulder and start a little bit more on the inside than what they would normally, making sure they give him only the outside break.

Because at least if they've done that, and Cooper still tries to step the defender on the inside, he would have to go extremely lateral to do that, which would then compromise the attack.

It's all about body angle, painting the picture to him that he has only one option and doing so with pressure on that inside shoulder. That's the good way to defend him and could be the key to the game.

There are other dangerous players in that Reds side - Will Genia, Ben Tapuai, who knows what James O'Connor can do. But, in my mind, if the Chiefs can shut down Quade Cooper they'll be halfway to winning the game.