The former Hearts scored a superb goal to double Rangers' advantage, having already set up Lee Wallace for the opener.
Dean Shiels then put the gloss on the victory but it was Templeton who stole the show with a man of the match display as Rangers moved 12 points clear at the summit.
McCoist said: "He's one of those players who will make something happen.
"He will give the ball away as well, which you have to accept with players with great talent.
"They will try things that won't always come off but, when they do, they're certainly worth waiting for.
"I thought his pass to Wallace for the first goal was exceptional but the second goal, you will struggle to see a better goal all day.
"It was a magic goal. It just came back onto his right foot and he slewed it into the top corner. It was a wonderful finish."
McCoist added: "I definitely think we can play better, and we will play better, but you've got to be happy with a 3-0 victory at home.
"We can do more in forward areas but I thought we looked strong defensively again.
"We were pretty solid, with Ross Perry and Chris Hegarty coming in and doing well. It's been a good day's work."