CONCUSSIONS have caused concern for the senior coaches of both sides following Melbourne's thrilling two-point win over Brisbane on Sunday afternoon.

Demons defender Harrison Petty left the field following an unusual incident in the third quarter, when a kick sprayed off the side of his boot deep inside defensive 50.

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Having spent some time on his haunches, Petty then went to his teammates - seemingly in some distress - and he was eventually helped from the field in the hands of trainers.

Dees footy boss Alan Richardson told Channel Seven during the game that the club was "bemused" by the incident given no one was near him at the time, and coach Steven King said they were still in the dark as to what transpired.

"We're still having a bit of a look at that. It was potentially a bit of a delayed concussion or something ... we're not 100 per cent sure yet," said King.

"He was complaining of some blurred vision so we'll do all the tests tonight and tomorrow and I'll let you know as soon as we find out. But obviously not great.

"We're obviously going to take it pretty seriously and we'll do our due diligence to make sure he's okay."

For the Lions, defender Noah Answerth was bumped by Melbourne's Kysaiah Pickett and subsequently collided with Melbourne forward Brody Mihocek, leading to a concussion.

It was Answerth's first game back from an extended break after he suffered a concussion in a marking contest against St Kilda in round three, with coach Chris Fagan pointing to the 26-year-old's history with concussion.

"I didn't see it. I was a little bit surprised when he came off and they told me that he was in the protocols," Fagan said.

"He's had a few concussions. So we're in the lap of the gods on that one. The main thing is what's good for his health."

The Lions were down two fit players on the interchange in the final term with Jarrod Berry (calf) and Bruce Reville (cramp) joining Answerth on the bench.

The 4-2 Demons remain undefeated at their home ground in 2026, with King saying the MCG brings the best out of his players.

"It's our home as a footy club and we've loved playing here," said King.

"I think the boys get excited about playing in front of their members and their supporters and there's no better place you'd rather play than at the MCG.

"So whether it be on a Friday, Saturday or Sunday, it's a privilege to play here, so we love it."

King acknowledged that Sunday's win was his best in his short time in charge.

"I think so. I think Gold Coast (in round four) were hot coming here as well. And then (the) back-to-back premiers here, it's such a huge game for their players, for Dunkley and Neale (who both played milestone games on Sunday).

"I think six games in, when you looked at the draw and saw Brisbane on it, you hope you compete and you'd love a win. So to walk away with four points today is a great result."