Hearts boss Craig Levein felt St Mirren midfielder Kyle Magennis should have been sent off as he watched his side go down 2-0 in Paisley.
The 20-year-old was only booked by referee Craig Thomson for his 38th-minute challenge on Michael Smith, but Levein felt it merited a harsher punishment.
Instead, he watched his side fail to win or score for the fifth game running as Adam Hammill bagged a brace, including a screamer from 45 yards.
Levein said: "I thought it was a bad foul. He was going off the top of the ball and it should have been a sending off. It's another thing that you can put on the list of things that didn't go for us.
"It's similar to the Kilmarnock game in that we had plenty of the ball. We created chances, maybe not as many as we should have, and didn't take them as they arose.
"In moments like these when things aren't quite going for you, or don't seem quite as easy as they have in the past, the last thing you need is someone to score from 45 yards and that's what's happened to us.
"When you should be in front and go behind, the opposition feel better about themselves and have something to hold on to. Our crossing today was poor, that's not something I usually level at the players as it's usually excellent, and we didn't create enough."
St Mirren boss Oran Kearney was delighted to finally get his first win since replacing Alan Stubbs in the Simple Digital Arena hotseat.
The Northern Irishman had picked up just two points in nine games but Hammill's efforts gave his side their first win in 12 matches.
Kearney said: "It feels good. I think the journey our guys have been on since I've been at the club, it's nice to finally get something tangible.
"We felt it was coming. We felt particularly in the last three or four weeks our performance levels have got stronger and stronger even against Rangers here and particularly second half against Dundee.
"You just have that sense of it and I think probably today, particularly pre-game, I just had a real good feeling today that it was the day they were going to deliver and to a man they did.
"We've been on that run of bad luck and decent performances then good performances, but we haven't quite had the result to go with it.
"I've seen our lads trying to deal with defeat after defeat and the character they've shown, and now I'm very hopeful this will be a good release for them. Ideally we want training to go up another notch next week and use this as a catalyst."
