United stretched their unbeaten run to three games but had to settle for a point in the Highlands.
The game's major talking point came when Jon Daly claimed a second-half goal only for the officials to rule the ball had not crossed the goal-line before goalkeeper Ryan Esson clawed it back.
McNamara said: said: "From the angle I was at, it looked as though the ball was over the line, but the linesman has not given it, which is disappointing.
"I thought we merited the three points. Over the 90 minutes we were the better team, especially in the second half, but we just didn't take our chances."