The North Warrnambool Eagles junior, 17, was entering his second year at Scotch College and had been pointed towards the Chargers to further his career.

But the prospect of running around in the elite junior competition as a bottom-age player seemed out of reach at that stage.

“At the start of the year I never thought I’d be in the team, but I kept throwing everything at it, kept giving my best,” he said.

That persistence earned reward when Oakleigh released its list for 2015. But a greater prize – a premiership medal – could yet be his.

The Chargers meet Eastern Ranges in the TAC Cup grand final at Docklands on Sunday, a match certain to attract the eyes of AFL club scouts.

Johnstone, who is ineligible to be drafted until 2016, said he was excited to feature in his second decider.

He helped the Eagles to a Hampden league under 16 flag last year but admitted “this will be the biggest grand final for me”.

“I never thought I would be playing in the grand final,” he said.

“Last week (in the preliminary final) everyone wanted it and realised we have a chance to be the best team in the comp. We all put our hearts and souls into it and came out with a win.”

Johnstone said he had told himself to “relax and play your normal game, don’t treat it any different”

“It all comes down to the way you handle yourself. I’m trying not to think about it too much, I’m trying to relax,” he said.

“I’m not nervous now but I might be before the game in the rooms. I think most of the boys will be. But once we get out there and have a kick of the footy, the nerves will soon go away.”

Johnstone said he idolised Essendon forward Matthew Lloyd during his childhood, while his father Kieran had been his biggest influence.

His emergence at the Chargers has made him realise how much he wanted to play AFL.

“It’s certainly hit me now and got me thinking a bit that if I put my mind to it and commit and dedicate myself to that dream I could fulfil it one day,” he said.