His 2025 campaign has been a crucial and underrated part of Geelong's success to this point, but on Friday night, Oisin Mullin showed that his game translates to the big stage, announcing himself to the football world in a big way.

The budding Irish star has been thrust into challenging negating roles against some of the competition’s best players throughout the year, but perhaps his biggest test came in the Qualifying Final, when he was sent to Brisbane on-baller Hugh McCluggage. 

In a clear sign of how far his game has come this year, Mullin completely blanketed the Lions star and nullified his impact, holding McCluggage to just 14 disposals which was his lowest total since Round 1 of the 2023 season.

He was also able to hold McCluggage to just three clearances, well down on his season average (5.8) and just one score involvement, a telling factor in Geelong's triumphant performance at the MCG. 

Embracing the moment and enjoying the challenge was Mullin’s motto this week, as he said his new role is helping to fast-track his development.

"It is so good, it is what Finals footy is all about," Mullin told Cats Media. 

"The atmosphere was unbelievable and everyone was up and about, we got the result we came here for. Everyone is delighted.

"It is definitely something I embrace [tagging]. The coaches put a lot of trust in me to do that, to matchup against players of Hugh's calibre.

"It is enjoyable, and it brings you to the ball as well at times which is good. It helps my learning in the game."

One of the best moments in Geelong's barnstorming performance came late in the first quarter, when Mullin roved the front of a pack and quickly snapped through a brilliant goal, the first in his AFL career. 

He was made to work for it after kicking seven straight behinds across his first 40 games at the top level, but the buildup was more than worth it as he brought the MCG to its feet. 

What made the moment even sweeter for Mullin was that his parents were in attendance, the Irishman talking through his goal with Cats Media following the game. 

"It all happened pretty quickly," Mullin said. 

"I got a bit excited after, I was out of breath for the rest of the quarter as it played out but it was definitely pretty special.

"My parents landed over here on Tuesday, so I saved it for however many games I have played.

"I have kicked about seven or eight behinds so I was just saving it for them to get over, but I was delighted to do it while they are here."