The impressive winner came from Niall McGinn in the 18th minute and was hard luck on the hard-working visitors as they ended the night languishing at the foot of the SPL table 15 points from St Mirren.
"It's a hard one to take because I think we dominated the second half and created chances in the first half. I can't fault the boys for effort, we just need a wee bit more quality in the final third," he said.
"It's just the finer details we're not doing well enough at this moment in time."
The only goal of the game frustrated the boss after McGinn received the ball on the halfway line and shuffled past two men before unleashing a low drive which bounced just in front of Rab Douglas before nestling in the back of the net.
Smith said: "We've spoken about the goal in the dressing room. These are the small margins that win or lose games.
"We switched off for a very short period of time, lose a goal, and then the chances that come along should be taken."