Fair enough for a rugby league convert hailing from Brisbane - "or Brisvegas as some call it" - who was lured to Canberra to join the ACT Brumbies academy.

The 20-year-old Gungahlin Eagles lock stands at 204 centimetres and tips the scales at about 120 kilograms, but he is still learning the ropes in the 15-man code after a highlights reel left tongues wagging around Australian rugby last year.

"I feel a bit stupid sometimes, being from a league background people are like 'this person has played for them'. I'm like 'should I have heard of them?'," MacDonald laughed.

"I'm playing with people I've never heard of but I'm told they're good. You give them a quick Google search and quickly get impressed by it."

MORE RUGBY UNION

How about the man lining up at flyhalf for the Eagles in their John I Dent Cup semi-final clash against the Tuggeranong Vikings at Viking Park on Saturday? Did MacDonald have to research Matt Giteau, the Wallabies great with 103 Tests to his name?

"Nah, had a bit of an idea on who he was," MacDonald said.

"He brings so much. I love playing with him as well, when we're behind the posts after they've scored some points, the chat he brings is enormous.

"Especially being inside him in the defensive line, at the back end of the game when you absolutely don't have a lot left in the tank, you can almost be blindfolded and listen to what he tells you to do.

"It makes it a lot easier on our big boys, having someone to guide them around."

The Eagles will face Vikings for a spot in the decider while the Uni-Norths Owls take on the Canberra Royals in the other semi-final at ANU North Oval.

Gungahlin enter the grand final playoff hot off the back of a 62-0 thrashing of Royals, when the return of Brumbies trio Mack Hansen, Issak Fines and Tom Ross - the prop who gives MacDonald "a big cushion to scrum behind" - took the Eagles to another level.

Now MacDonald is determined to follow their lead through the Brumbies ranks as he plies his trade under Marco Caputo and lineout guru Ben McGee at club level.

"When I came down here I was definitely a player to put some time into, I still don't think I'm there yet, where I need to be as a lock," MacDonald said.

"If I'm not jumping well in a lineout or messing up a scrum, as long as I'm carrying hard and hitting people harder, I've got to keep doing that, that's my strength.

"Having a coach like Choc, he is massive on physicality. I'm making sure I do everything right, trying to get the physicality right, that's when the game comes together.

"Ben McGee is an expert and lineout guru. He's put time into me, and the players around have been patient.

"I can definitely test a lot of people's patience at times at training. They've put a lot of time into me, I've progressed and still need to progress a lot further, but it's going well."

JOHN I DENT CUP SEMI-FINALS

Saturday: Tuggeranong Vikings v Gungahlin Eagles at Viking Park, 3.30pm; Uni-Norths Owls v Canberra Royals at ANU North Oval, 3.15pm.

ACT WOMEN PREMIER XVs SEMI-FINALS

Saturday: Uni-Norths Owls v Goulburn at ANU North Oval, 1pm; Canberra Royals v Tuggeranong Vikings at Viking Park, 1.15pm.