And the Scotland fly-half is desperate to get the win that will keep his hopes of a PRO14 Final appearance and a silver-lined departure alive.
Speaking to BBC Scotland, Finn said: "You don't want the semi-final to be your last game; you want to go on to the final. It's not sad having my last game here in the semi-final rather than in a game that doesn't mean anything.
"There wouldn't be a better game to have your last (home)Fin wants perfect Scotstoun game than a semi-final.
"Scarlets beat us quite comfortably recently and they are a top side. They are definitely one of the best in Europe.
"They have had three games of knockout rugby already this season (in the Champions Cup), so we'll have to be at our best. It's our first time for knockout rugby this year. There's a lot of experience in our team, so it's good to have that going into these games.
"It comes down to these 80 minutes. Some boys started pre-season on 1 June. If it doesn't go our way, it's 12 months just to get to the semi. So there's a lot riding on the game, but at the same time that's why we play - for these big occasions, these big games."
Finn was an apprentice stonemason when he won an academy deal six years ago. He said: "I was quite happy being a stonemason and living a normal life.
"When I got offered an academy contract it was less money and probably more hours travelling to play for Ayr. It was tough but I just accepted that.
"The first year I was here, Glasgow got to the semi-finals, so I've always known Glasgow was a top-four team. A lot of the older boys say in years gone past they were never like that.
"It's different now for young boys coming through. They see Glasgow as one of the top teams in the league and you almost don't appreciate what the older boys went through to get the club here.
"When I first started playing here I think there was about 5,000 fans. Throughout the whole season this year there's 7,500, and we're putting in 10,000 for the weekend. It shows how the sport is growing and how this club is growing.
"It's been amazing for me - Scotstoun, the fans. That's probably given me the best six years of my life so far.
"It's given me things that six years ago I would never have thought of or thought possible. It's chucked a lot of challenges at me that I wouldn't have thought I'd be facing. As a person its made me grow and as a rugby player its definitely developed my career."