St Johnstone manager Tommy Wright is aggrieved about referee Willie Collum's decision to award St Mirren a second penalty and send off Frazer Wright.
"My instinct is that Frazer's one isn't a penalty," Wright told BBC Radio Scotland. "I think he's used his strength to stay in front of the player and nick the ball.
"I believe the referee didn't give it. I think it was the linesman on the other side."
It was the Perth side's first defeat in four Scottish Premiership games and they sit seventh in the league on 12 points, four ahead of St Mirren.
The Buddies' Kenny McLean opened the scoring before Steven MacLean equalised.
In an all-action second half, Paul McGowan slotted St Mirren ahead again only for Nigel Hasselbaink to level.
The Buddies' captain, Jim Goodwin, missed a penalty and, when they were awarded another, McLean was successful.
However, Rory Fallon clawed the Perth side back again before Steven Thompson had the final say.
"We put a lot into the game and scored three away from home," said Wright.
"I'm really disappointed for the players because I thought they put a lot into it.
"It was an entertaining game, but at times I think it was too open.
"We showed a lot of character to bounce back every time that they scored and particularly going down to 10 men, so I've nothing but praise for the players.
"We've been pretty solid defensively all season. I just think the game was open. Both teams wanted to win it and left themselves a bit exposed."