The match also brings the two Crusaders' No10s together - Mo'unga and Mitchell Hunt, with the former fresh off a week with the All Blacks as an understudy to the injured Beauden Barrett before the test against the Wallabies in Brisbane.
"I guess it was awesome to be part of that last week and know I'm right in the mixer, but for me I still have to be as consistent as I can and I still have to nail my job tomorrow night," Mo'unga said.
"You start to see why they're the best in the world and what separates them [from the rest].
"I was lucky enough to be rooming with Beauden Barrett so to see how he operates during the week - I'll take a lot out of that.
"Finals footy comes down to a few key moments and we just have to make sure we nail them. We know a lot about them and they know a lot about us and it's about who can do those things a bit better."
Mo'unga's stint with the All Blacks meant he was unable to play for Canterbury in their semifinal victory over North Harbour in Christchurch last weekend. "It was hard - when you invest so much in a campaign it becomes tough when you leave and the boys play such a big match."
Brett Cameron wore the No10 for Canterbury in that match and will start the match at AMI Stadium on the reserves bench.
For Mo'unga, this final is the beginning of a big weekend. The day after he will fly to London to prepare to play for the Barbarians against the All Blacks at Twickenham the following weekend and then join up with Steve Hansen's squad in France.
"It's an awesome opportunity and it's going to be a big occasion... it will be something I remember for a long time," he said.
Mitre 10 Cup Premiership final: Canterbury v Tasman, AMI Stadium, Saturday 7.35pm.
Canterbury: George Bridge, Josh McKay, Tim Bateman, Rob Thompson, Braydon Ennor, Richie Mo'unga, Mitchell Drummond, Luke Whitelock (c), Billy Harmon, Tom Sanders, Dominic Bird, Hamish Dalzell, Siate Tokolahi, Ben Funnell, Alex Hodgman. Reserves: Nathan Vella, Chris Gawler, Oliver Jager, Reed Prinsep, Tom Christie, Jack Stratton, Brett Cameron, Inga Finau.
Tasman: Will Jordan, Tomas Aoake, Levi Aumua, Alex Nankivell, James Lowe, Mitchell Hunt, Finlay Christie, Jordan Taufua, Vernon Fredericks, Ethan Blackadder, Shannon Frizell, Alex Ainley (c), Tyrel Lomax, Andrew Makalio, Siua Halanukonuka. Reserves: Ti'i Paulo, Tom Hill, Ryan Coxon/Drew Petelo, Pari Pari Parkinson, Pete Samu/Braden Stewart, Billy Guyton/Ben Finau, Tim O'Malley, Trael Joass.