I think it's possible. As Paul Kent points out, Souths are a team who plays in 'waves'. Or at least, they attack in waves. They wont be constantly threatening like some other top four sides (notably Melbourne).
If we can play them through the forwards and only spread the ball after we've gone forward (rather than be too lateral and try to spread the ball early) that will really help our cause. If M. Jennings plays at right centre instead of left, to help stem the tide of South's attack down that side, that will help. If we can try to contain Walker to some degree and put as much pressure as possible on Reynolds' kicking game. And, of course, if Moses can be patient and controlled in his game - then, sure, we can win this. I feel for Waqa Blake. He must be as nervous as shit. If Jennings has been working with him a little bit this week, then I think having him (Waqa) on the right wing where Jennings can keep talking to him, might be a good idea.
But, yeah, we can win this.