10-men Saints fell to a 3-0 defeat to Aberdeen at Pittodrie with Thierry Small shown a straight red card in the first-half following VAR intervention.
The result - coupled with Hibernian's win over Celtic - means the Buddies finish the season in sixth place. While there will be disappointment tonight, a historic season - in which we finished in the top six for the first time in this format - represents our highest top-flight finish since 1985.
Despite doubts over the fitness of Small and Curtis Main both managed to make it and Stephen Robinson named the same starting eleven that drew 2-2 with Celtic on Saturday.
Aberdeen took the lead on 14 minutes when Leighton Clarkson despatched a free-kick into the net from 20 yards.
Saints best chance for an equaliser came less than 10 minutes later when Alex Gogic rose to meet a Small cross. The Cypriot midfielder's header forced a good one-handed save from Dons goalkeeper Kelle Roos who tipped over. Gogic was first on to the resultant corner, but nodded wide.
St Mirren's hopes of finding an equaliser were dealt a major blow when Small was shown red after a VAR check following a foul on Bojan Miovski who had to be stretchered off. Initially the loanee was shown yellow, but referee Don Robertson consulted the monitor and upgraded to red which Saints could have no complaints about.
Aberdeen almost hit Saints on the counter with 10 minutes of the half remaining. Duk ran clear but had his effort saved by Carson. The Saints goalkeeper couldn't gather at the first attempt and had to be quick to deny the follow-up.
The Dons did double their lead on 42 minutes with Graeme Shinnie heading home to make it two-nil. Carson had to push away Joe Shaughnessy's deflection of a Marley Watkins' cross, but the ball spun up in the air which allowed Shinnie to nod into the net.
Shinnie added his second and Aberdeen's third just four minutes into the second-half. The Dons midfielder met a low ball in from Ylber Ramadani and forced under Carson.
Saints first opportunity of the second-half came just after the hour mark when a strong run from half-time substitute Kieran Offord saw the young forward fouled 25 yards from goal. Strain stepped up to take the free-kick but Roos was down well to gather.
Main could have pulled one back with just over 20 minutes of time remaining when he raced on to a Gogic ball over the top and went one-on-one with Roos. The forward's effort was powerful but the Dons keeper stayed big to block. Mark O'Hara was next to test Roos with a long-range drive that Roos had to get both hands behind to push away. That was to be the last opportunity for either side as the Dons picked up the points.
Full-Time: Aberdeen 3-0 St Mirren
St Mirren: Carson, Fraser, Shaughnessy (c), R.Taylor (Tanser 46), Strain (Gallagher 75), Baccus (Offord 46), O'Hara, Gogic, Small, Kiltie (F.Taylor 80), Main (Jamieson 75)
Subs Not Used: Urminsky, Kenny, Dunne, Boyd-Munce
Aberdeen: Roos, McCrorie, Pollock, McDonald, Scales, Shinnie, Ramadani (Barron 71), Hayes, Clarkson, Duk (Bavidge 75), Miovski (Watkins 34)
Subs Not Used: Lewis, MacKenzie, Morris, Coulson, Duncan, Richardson
Referee: Don Robertson
Assistant Referee: Steven Traynor
Assistant Referee: Paul O'Neill
Fourth Official: Chris Fordyce
VAR: Euan Anderson
Assistant VAR: Sean Carr
