The Saints captain is aware of the threat that Souths pose with ball in hand, especially if given opportunities through errors.
“If we give South Sydney as much possession as we have given other sides in the opening two rounds then they will punish us a lot more ruthlessly than we have been,” Wilkin told his club’s official website.
“We are aware of that and have some easy improvements to make.
“Our defence has been exceptional from the back end of last year to the start of this. Most attention has gone into that in the off season.
“That doesn’t guarantee a good night on Sunday – we have to work hard and take that into the game.”
How Saints defend will also be key to the outcome, according to Wilkin.
“We’ve started well and haven’t conceded a lot of points,” he added.
“The cornerstone of any side that wants to win trophies is defence. If you are loose defensively you are liable to be beaten in the big games. I don’t think us or Souths could be called loose in defence.
“The atmosphere will be special and vibrant. We can’t wait.”