Referee Calum Murray admits he should have added more injury time in Sunday's Celtic, Rangers clash. However, his decision to ignore a Rangers penalty claim in Sunday's draw against Celtic was correct.

Despite five substitutions and Celtic midfielder Scott Brown being treated for five minutes, only two extra minutes were added.

Murray told BBC Scotland his only major mistake had been in his timekeeping.

He said: "I stand by every major decision I made, but injury time should have been doubled.

"I misjudged how long Brown was down injured, and I also didn't allow enough time for the substitutions."

The official was glad to have come through his first Old Firm game. "It's great to have done an Old Firm game," he said.

"You've got to think on your feet very quickly.

"The players helped in ensuring that the match passed without major incident."