After Rangers' victory - critical in their pursuit of the SPL title - United boss Levein said: "We had a blatant penalty and he bottled it.
"Not only is it a penalty kick, but it's a sending off for Davie Weir. But he didn't want to do it because this game meant so much to Rangers."
McCurry himself has offered an explanation on the Whistleblower section of the SFA website: "In the 55th minute of the match Rangers FC were in possession of the ball and attempted to clear it from their defensive area. As is normal practice, I started to run towards the halfway line, anticipating the ball being cleared from defence.
The clearance, however, was not successful and the ball struck Noel Hunt of Dundee United, who then played a very quick "one-two" allowing him to chase the ball into the penalty area closely followed by David Weir of Rangers.
"At this point, given the very quick change of the direction of play, I was caught out of position and my line of sight was partially obstructed by another player.
"I saw Noel Hunt fall to the ground with David Weir in close proximity behind him. As my vantage point was extremely poor it was not possible for me to say what or, if any, infringement had occurred.
"Given this significant doubt in my mind it would have been improper for me to simply conclude that an infringement had occurred on the opposite side of the field of play from me. On this basis, I had no option but to allow play to continue amidst the appeal for a penalty kick.
"I have now had the benefit of seeing the incident again on television. I believe that were it not for the fact that I had been caught out of position by the quick transfer of play I would have awarded Dundee United a penalty and would have cautioned the Rangers player David Weir.
In my opinion there was another defender in close proximity with the possible opportunity to make a defensive challenge on the attacker.
"In the 71st minute Dundee United were in possession of the ball and Danny Swanson shot towards the Rangers goal from approximately 30-35 yards. The ball appeared to me to be deflected off a Rangers player and entered the goal.
"As I turned to award a goal to Dundee United it was brought to my attention that the stand-side assistant referee had his flag raised signalling that an offside infringement had occurred. I also noticed that a Dundee United player required medical treatment.
"Having made sure that the player received the required treatment, I then went across to the assistant referee and confirmed that he was signalling for an offside infringement. He confirmed this was the case and informed me that a Dundee United player had been in an offside position and that he had played the ball prior to it entering the goal.
"I informed the assistant referee that it appeared to me that the ball was deflected off a Rangers player. The assistant referee told me that he had not seen it touch a Rangers player but had definitely seen it played by the Dundee United player, David Robertson.
Given that David Robertson was behind the Rangers player, my view was such that I could not tell if the ball had been played by Mr Robertson last before entering the goal. Consequently, I decided to accept the advice of my assistant referee.
"Again, having had the opportunity to review the incident on television, it is clear to me that the ball is not played by the Dundee United player Robertson who was, however, technically in an offside position and was in close proximity to the ball.
"I can understand the difficulty faced by my assistant referee in this incident and why David Robertson may have been considered offside.
"Again, with the benefit of seeing the incident again numerous times on television, I consider it would have been more appropriate to conclude that the player, David Robertson, was not involved in active play and would have allowed the goal to stand."