But McCoist admitted he was relieved to come away from Borough Briggs with all three points courtesy of Lee McCulloch's late penalty.
Black was sent packing for a second booking in the 86th minute after a tackle on Elgin's Gavin Morrison which McCoist said was not worth another caution.
"The sending-off was extremely harsh," he said. "He got booked for three or four fouls, the ref said, and rightly or wrongly he was on the yellow card. We told him he's got to stay on the park and stay on his feet, and I thought he did.
"The game was hard-fought but I don't think there was a bad tackle in the whole game. It's just because it's changing, the laws of the game are changing to the detriment of the game.
"We've got a player sent off, in my opinion, wrongly. I thought the ref handled the game very well but sadly I think he got that one decision wrong.
"I was tempted to sub Ian because we need 11 men on the park but as it happens we got away with the sending-off. I felt there was always a big possibility of him getting sent off after receiving the yellow card, just because of the way he plays the game. But, to counter that, I did think it was extremely harsh."
McCoist also revealed that striker Kevin Kyle has been released by the club, and he added: "Kevin has left the club by mutual consent. We have terminated his contract and he goes with our best wishes for the future."
Elgin manager Ross Jack said his players felt the penalty decision leading to McCulloch's winning goal was harsh. Sean Crighton was penalised for a foul on Lee Wallace in the box but Jack said his team had told him the contact had been minimal, if any.
"We were coping very well with everything they threw at us so to lose to a penalty was tough," he said. "I know Rangers are saying it was definitely a penalty but our boys are saying there's no way anybody touched him. But it was given and there's nothing we can do about it."
- Sports & Recreation