Drew Petrie says the North forwards will be better prepared for the Richmond defender’s tactics next week if the sides face off in an elimination final.

The vice-captain said he and fellow forwards Ben Brown and Aaron Black were constantly pushed under the ball on Friday night while Dermott Brereton went a step further suggesting it was “tunnelling”.

“It definitely is an employed technique by the Richmond backmen, it’s not reportable because they don’t go overboard with it but they have a spoiling technique against the tall forwards ... they almost tunnel you when you are stretching for the ball on the lead at the highest point, their body comes through the drop line and forces your hips forward and it takes your legs from underneath you,” Brereton told SEN.

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Petrie said the tactic wasn’t illegal, but admitted it was hard to combat.

“It’s a frustrating thing as a forward when you know you’re sitting under it and you’ve got a defender breathing down your neck and they’re just edging you under it,” Petrie said.

“It’s really hard to stop once they’ve initiated that contact and they’ve run you under the footy.”

Tunnelling is a reportable offence and can lead to serious injury.

“One of our blokes got paid a free kick ... I heard the umpire blow the whistle and call out “tunnelling”,” Petrie added.

“I guess it can be slightly dangerous if a player loses his feet and lands flat on his back, but I think it’s good defending and I think our defenders employ similar tactics to try and run their opponents off the line of the footy or underneath the footy.

“Providing it’s done properly it’s a fine tactic for all defenders to use but if it becomes a dangerous movement a free kick’s got to be paid.”