When North Melbourne key defender Lachlan Hansen landed awkwardly after a marking contest against Essendon on Friday night he initially feared he had stirred up the groin and hip issues that ruined his second half of 2014.

The key defender dragged himself to his feet in the second quarter and felt groin soreness. He seemed restricted when he tried to run and soon retreated to North's interchange bench for treatment.

"I landed awkwardly on both of my knees and just stretched the groin. I thought I was in a bit of trouble at the start there but I came off, got assessed and after a couple of minutes I was fine," Hansen told AFL.com.au after the game.

"The first thing that went through my mind was 'Oh no, not again, I've done what I did last time'.

"But the surgery and all the strengthening I've done must have helped because I was able to play out the second half and it's all fine now, so it's a good result."

Hansen was enjoying an outstanding season last year before his groin and hip problems became increasingly worse, eventually sidelining him for six of the Roos' last seven games including all three finals.

The 26-year-old's rehabilitation from his post-season surgery meant he was not cleared to resume full training until the week leading up to round one.

He returned to North's team in the round six win over Richmond, having played two lead-up games with Werribee in the VFL.

Hansen was understandably rusty against the Tigers and missed a few marks he would normally clunk early in Friday night's 11-point win over the Bombers.

But 2006's No.3 draft pick soon found his touch and started to get off his man and take the intercept marks that have been his trademark since he was allowed to settle in defence early in 2013.

Hansen was one of North's best players, finishing with 24 possessions, a game-high 14 marks (three contested), an equal team-high five rebound 50s and two inside 50s.

Hansen downplayed his performance but acknowledged his touch was starting to return.

"I'm starting to feel fit again and working in with the other backs and the boys," he said.

"It was good to get a few grabs tonight."

Hansen was more excited by North vice-captain Drew Petrie's performance against the Bombers.

Starting in his usual position deep in North's forward line, Petrie kicked two of the Roos' first three goals at a time when his teammates were struggling to convert set shots.

The veteran spearhead continued to compete with his usual ferocity inside North's forward 50 but also drifted down to defence at times – particularly late in the game – where he short-circuited Essendon attacks with some telling marks.

Petrie finished the match with 19 possessions, 12 marks (three contested), four rebound 50s, three inside 50s, four tackles – and three votes from Hansen.

"I was more excited for Drewy taking those marks (in defence) than anything I did. I think you could see me in the background fist-pumping whenever he took a mark," Hansen said.

"He was great up forward and then when he was able to come down back and clunk them like he did, it just gives the boys a massive lift.

"I thought he was best on (ground) by a mile."