CONSIDER the reasons for North Melbourne’s dominance of the Western Bulldogs and the choices are aplenty.

Milestones? Maybe. Form? Not always. Venue? No.

Look for one and the Roos just match up well against a side that has only lost three games this season.

North handed the Bulldogs their first defeat of the year in round nine, a thriller decided by three points, and will look to strike again when it hosts them at Telstra Dome on Sunday.

The second-placed Bulldogs haven’t beaten the Roos since round eight, 2005 and utility Scott McMahon has played in three of his side’s four victories since then.

When asked how North Melbourne can sustain its run, matching a fifth straight win over the Dogs with five on the trot since the mid-season bye, McMahon’s response is simple.

“I think the team just has to stick to their structure,” the 22-year-old said. “What Dean (Laidley) has set out and the assistants have set out, we just have to stick to that.

“On our day we can beat any team, so it just pretty much comes down to that and just our pressure and our tackling around the ground.”

It was the Roos’ commitment to its game-plan and personnel that generated the last triumph after the Bulldogs led by 24 points at half time.

Nathan Thompson finished with four goals, Hamish McIntosh prevailed in the ruck, Brent Harvey returned from his first-term concussion and Adam Simpson and Brady Rawlings maintained the midfield’s output once Daniel Wells limped from the field.

Granted, there was also the motivation of Harvey’s 250th game and this week the Roos will seek a similar outcome for the widely-respected Drew Petrie – who plays his 150th.

Petrie, who announced a three-year contract extension during the week, continues to lead his younger teammates by example, McMahon included.

“You always know he’s going to give his 120 per cent and he’s going to pretty much die if he could to help us win, which is similar to everyone,” he said. “With that size, he’s just got that presence about him as well.

“It shows with the stuff that he does on the ground. He’s a tremendous leader. With a few of his spoils there in the last quarter [against the Brisbane Lions last weekend], he nullified (Jamie) Charman and just his work-rate around the ground as well [was so important].”

The win over the Lions was McMahon’s eighth game of the season and, by his own admission, 2008 has been challenging.

Elevated from the rookie list at the end of 2006, the South Australian played 16 games last year including every match from round 13 through to the preliminary final against Port Adelaide.

He started this year with Werribee in the VFL, but finally found touch that warranted his selection for the round eight clash with West Coast.

“I struggled a bit this year,” he said. “I came back and just wasn’t playing as well as I would have liked and just took a while to hit my straps.

“I got a few good games under my belt and then got into the seniors and [now I’m] just trying to play my role and put my best foot forward each week.”

He’s receptive to playing forward or in defence, but well-rounded performances suggest McMahon’s more suited to a role in attack.

Then again, his composure in front of goal to kick the sealer in last week’s win fell second to a show of courage when running back with the flight of the ball to spoil a certain mark for Lions spearhead Jonathan Brown.

“[My aim is] to stay in the team,” he said. “I just want to keep improving week in, week out and hopefully just keep the winning streak going so we have the opportunity to play in September.

“I like it up forward but I also like it down back, so it just depends where the coach wants to put me.”

Wherever that may be on Sunday, trust McMahon to have an impact.