MELBOURNE tagger James Harmes has conquered the game's best in recent weeks.

But as the club looks forward to its first final in 12 years, the improving Demon is refocusing his attentions back to where it all began – in a crucial run-with role against Joel Selwood.

Harmes had never played a full game as a tagger prior to being handed the key job on the Geelong captain ahead of his side's round 18 clash with the Cats.

Used fleetingly and sporadically in the position before, it was the first time Harmes had been asked to put all of his effort into stopping the opposition's best player for an entire match.

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He relished the role, producing arguably the best performance of his career to date against Selwood and growing into a full-time tagger in the month since that important display.

Now, he's ready to face the Cats skipper once again – even if his coach Simon Goodwin is still keeping his cards close to his chest.

"I'm not too sure who I'll be on, we'll see what happens," Harmes told AFL.com.au.

"'Goody' normally comes up to me later in the week and lets me know. I'd say either Joel Selwood or Patrick Dangerfield, but I haven't been told yet."

While Harmes is adamant he has not yet been informed who he will be standing alongside at the first bounce on Friday night, he has an inkling it's going to be Selwood.

The last time they met, when the Cats got over the line thanks to a Zach Tuohy kick after the siren in July, Selwood was limited to just 16 disposals and four clearances.

It was the Geelong captain's lowest output of the season, and it provided Harmes with plenty of confidence going forward.

"He works really hard, he's pretty strong and he's a real competitor," Harmes said.

"He's definitely one that I'll have to watch around the stoppages. You can easily lose him in there."

While Harmes' job on Selwood won plenty of plaudits, it was actually the game prior against the Western Bulldogs when Goodwin first approached the 22-year-old about being used as a tagger.

Dogs star Jack Macrae had won 25 disposals to half-time in that particular clash at the MCG, before Harmes was employed in his newfound position.

He kept Macrae to just eight touches in the second half, proving to the Melbourne coaching group that he had the ability to restrict the game's best.

"Jack Macrae had 25 at half-time and Goody came up to me and said that I'd be going to him," Harmes said.

"It was the first real tagging role I'd ever done and it just flowed on from there.

"It's different with each player, you've just got to be switched on the whole time. Quality players, they know how to get the ball. When you think they might not get it, they get it. So, the biggest learning is to stay focused and just do my job."

A feature of Harmes' performances as a tagger have been his ability to damage the opposition offensively, as well as stopping their best players with his defensive efforts.

In Melbourne's round 23 victory over Greater Western Sydney, Harmes kept Giants star Josh Kelly to just 19 disposals – while having 29 touches, six clearances and a goal himself.

It completed a five-match stretch where the developing on-baller has averaged more than 26 disposals and one goal per game, clearly the best period of his young career. 

"I don't think there's a secret behind it, it's more about getting the chance to play as an inside midfielder for most of the game," Harmes said.

"I've just been building a little bit of confidence with each week and building off that. I could always find the ball, it was probably my defensive work that would let me down a little bit. But I feel like that's in good stead now.

"I definitely feel like it's the best footy that I've played. It gives me a lot of confidence, especially playing the role on Selwood before … I know what I have to do to shut them out of the game and I'm really excited about Friday night."

Harmes is one of the many Melbourne players set to play their first final on Friday night, but his confidence is emblematic of the enthusiasm currently brimming within the club.

Despite two narrow defeats to Geelong already this season, he insists the young group has nothing to fear going into a clash with an expected crowd of around 90,000 people.

"We're not scared. We're not scared at all," Harmes said.

"We're actually really excited to get out there. I think if we bring our best footy, we'll be pretty hard to beat."