The Red Devils boss was baffled that his side did not earn a spot-kick after the left back was booked.
Wayne Rooney had missed a penalty earlier in the game for the Red Devils in a tumultuous game, but the Scot believes he should have had a chance to take another after the tackle saw the left back booked late on.
“For me it was a shocking tackle,” Ferguson told Sky Sports News after the game. “The referee’s booked him and if he’s booked him then I don’t know why it wasn’t a penalty. I must ask him.”
The tackle could have the Mexican forward out of action for a bit, but the United boss said he didn't know how long.
“We don’t know," he said. "We’ll have to wait until the morning but at the moment his leg is very numb, there’s very little feeling on it. He could be out for a couple of weeks, maybe.”