Sir Alex Ferguson has branded referee Olegario Benquerenca's decision to deny Manchester United a penalty in their 3-3 draw in the Champions League meeting with CSKA Moscow as one of the worst he's ever seen.
Midfielder Darren Fletcher appeared to be tripped in the area for a certain spot kick, but was instead booked for simulation.
Ferguson reviewed the incident during the game and was left shocked by Benquerenca's ruling.
"I can't believe it, I watched it on the camera at the side [of the pitch] and cannot believe that decision," he told Sky Sports.
"It was one of the worst I've seen in my lifetime. Unbelievable."
Antonio Valencia's late strike rescued a point for United, and despite the defensive frailties displayed in conceding three goals, the Scot was pleased with the overall performance.
He said: "We've lost three goals at home, and you don't like that.
"They got a surprise goal just after half-time and it gave them something to hold on to.
"But I thought the intensity of our play, particularly in the last 25 minutes, was terrific."