Police had to escort controversial referee, Charlie Richmond, from the field as players and officials converged on him after he had flourished 11 yellow cards during a competitive game which resulted in red cards for three St Johnstone players.
Both managers were in agreement that the number of cards was unjustified.
St Johnstone opened the scoring in the seventh minute after St Mirren had the oppportunity to clear up an attack but failed to take it.
The ball broke to Chris Hay whose fiercly-struck shot was diverted onto the bar by Craig Hinchcliffe but Michael Moore raced in to nod the ball into the net.
Moore shot narrowly wide and Hay's angular drive brought out a good save from Hinchcliffe as the Perth Saints piled on the pressure.
All the home team offered by way of threat was a Kevin McGowne header from a Ricky Gillies free kick which was easily gathered by Alan McGregor.
St Mirren equalised two minutes after the break. Simon Lapin turned trialist Steven Anderson on the left flank and crossed for John O'Neill to turn in the box and poke the ball past McGregor despite having his shirt tugged by a desperate defender.
Moore still troulbled St Mirren with his industry and pace but the sendings off mounted and substitute John Baird became the hero of the home crowd when he rose to a Kirk Broadfoot cross and looped a header over the dispairing McGregor from eight yards.