Celtic back on top of SPL
St Mirren defender Chris Innes deflected a Scott McDonald drive past Buddies goalkeeper Paul Gallacher to give the home side the lead in the 38th minute and Georgios Samaras made it 2-0 three minutes from the break.
Hoops boss Tony Mowbray was pleased with the points but reiterated his desire for good performances.
"The three points were the most satisfying thing," he said. "We try to play with style and we work on things but ultimately it's about taking the points and it's been a good weekend for us.
"But I will always be a performance-related coach because good performances give you consistency of results.
"You can scramble a victory every now and then but you ain't going to do it every week.
"If your performances are not of a good enough standard you are not going to scramble 1-0 or 2-1 wins every week.
"You will draw or lose games so we strive for high performances."
Mowbray refused to discuss reports that he had been in France on Friday night to watch Tours striker Olivier Giroud in a Ligue 2 clash with Angers.
He said: "There have been a lot of other trips over the last few weeks that people have not talked about but it's a part of a process that we are going through to try and identify footballers."
St Mirren boss Gus MacPherson had no qualms about referee Conroy's mistake, claiming an earlier infringement in the game had been more costly.
"Steve is a good referee and he will be highly embarrassed about that," he said. "It was an unusual mistake but I'm not upset.
"I'm more upset with the free-kick that we should have had before Celtic's first goal.
"We can't shout too loudly about it because we got possession back and gave it away again.
"So I'm not going to complain about clerical errors."