Simo Valakari tasted his first defeat as a manager in Scottish football after St Johnstone lost 3-1 in Paisley.
Benji Kimpioka grabbed the opening goal before having a second scratched off for handball.
Former Saint Scott Tanser equalised with a sublime curler from range before the Buddies improved in the second half.
A Mark O’Hara header and Jonah Ayunga’s late finish sealed the points for the home team.
Saints’ mini revival has been stopped in its tracks after two successive wins and impressive performances.
The McDiarmid Park men now drop to ninth in the table as St Mirren leapfrog them into seventh.
The Perth boss made one change to the side that beat Dundee 2-1 at the weekend with the injured Andre Raymond making way for Kyle Cameron.
The odds looked in Valakari’s favour – St Mirren were on a four-game losing streak.
But it was the home side who had the first chance where Perth keeper Ross Sinclair got low to deny Elvis Bwomono’s header.
St Mirren’s determination to kickstart some good form was clear.
But it was the visitors who grabbed the lead on eight minutes.
Matt Smith’s corner found the head of Jack Sanders, who directed goalwards for Benji Kimpioka to flick home.
The goal was initially halted for offside before VAR intervened and the Swede got his fifth league goal of the campaign.
Saints were getting a few decisions their way which was getting under the skin of the Paisley supporters.
It nearly got worse for the home crowd as Kimpioka smashed home on 19 minutes, only to have been judged to handle before his strike.
Blue shirts were darting with purpose any time they could break out of the high St Mirren pressure.
Just before the half hour mark Killian Phillips volleyed wildly over from outside the box as The Buddies struggled to create any clear cut chances.
Then from nowhere up stepped a former Saint with – there’s no question about it – a worldie on the half hour mark.
The ball came loose to Scott Tanser just outside the corner of the box and he curled a fine effort straight into the top corner.
Sinclair may as well have just sat down as it sailed in.
Marcus Fraser fluffed a close-range header soon after as the momentum fell firmly with St Mirren. Saints were struggling to keep possession. Toyosi Olusanya nearly benefitted from a robbed ball but struck wide five minutes from half-time.
Adama Sidibeh has not scored for club or country since a brace against Kilmarnock in mid-August. He thought he had finally broken his duck, but the Gambian was judged to have pushed over centre back Charles Dunne before pulling off a wonderful chipped finish over Ellery Balcombe.
VAR was centre stage once again.
The start of the second half saw St Mirren continue to force the issue from wide with a crosses – one wayward loft from Phillips even clipped the top of the crossbar.
Tanser again tried from distance without troubling Sinclair.
Saints couldn’t get out their half and were starting to lose ther shape.
And the pressure told on 57 minutes.
Good work down the right from Greg Kiltie saw a floated ball fall to Mark O’Hara who headed goalward. Sinclair got a touch before it deflected into net.
It looked a matter of time before it was 3-1 and it so nearly was.
Killian Phillips’ strike was ruled out for a foul after Steven McLean was called to the monitor.
Valakari sent on Makenzie Kirk, Barry Douglas and Graham Carey for Benji Kimpioka, Kyle Cameron and Matt Smith to shake Saints out of their funk.
The Perth side livened up instantly and were hovering around the St Mirren box.
Jason Holt fired over after good midfield build up between Carey, Drey Wright and Sven Sprangler as Saints hunted for an equaliser.
Last week it was Nicky Clark who grabbed the late goal to seal the points.
This time there was a late strike. But it was The Buddie this time, who made it 3-1 through substitute Jonah Ayunga who latched onto Mikeal Mandron’s flick on before firing high over a spreading Sinclair.
Line-up: St Johnstone – Sinclair, Neilson, Sanders, Cameron (Douglas 68′), Wright, Sprangler, Smith (Carey 68′), Holt, Sidibeh, Clark, Kimpioka (Kirk 68′).
Subs not used: Rae, McPake, Kucheriavyi, Keltjens, Franczak, Essel.
Referee: Steven McLean.
Attendance: 6042.