Ferguson rounded on referee Alan Wiley over the award of the decisive penalty.
"It was absolutely diabolical, " he told MUTV. "It is a major decision.
"If we're not going to get those decisions then we are under pressure."
Ferguson believes his team have not been getting the rub of the green from officials.
He said: "If we're not getting the decisions we deserve then we're going to have to perform really well. In the context of today, when (Cristiano) Ronaldo comes on, in the first minute he's grappled to the floor by Ballack.
"It was a clear penalty kick but no penalty was given."
The Serbian needed stitches and lost a tooth.
"He got kneed in the face by Drogba - no foul given, " said the Old Trafford boss. "He was dazed rather than concussed."