Rangers have struggled on their travels so far and, despite his frustration, McCoist said that he is determined to fix the away form.
"I just feel frustrated," PA Sport quotes McCoist as saying. "That's my over-riding feeling - frustration at not getting away victories in the division.
"At the same time, there is a determination to get it right and put it right and we will.
"We've lost a league game here today. We always knew it would be a lot harder than a lot of people were making out and it's certainly turning out that way."
The defeat leaves Rangers third in the league with 12 points from seven games.