Carlo Ancelotti saw Chelsea go five points clear at the top of the Barclays Premier League with a 1-0 win over Manchester United and then accused the visitors of trying to influence the referee.
In a stormy second half, Darren Fletcher waved an imaginary card at referee Martin Atkinson in an apparent attempt to get Chelsea defender Ricardo Carvalho dismissed for a tackle on Wayne Rooney. Carvalho had already been booked by Atkinson but Fletcher's attempt fell on deaf ears.
It was just one of a number of confrontations between the referee and players from both sides and Ancelotti said: "The Manchester players protested a lot. I don't know why. I don't like this. At the end of a very difficult match, all the players worked very hard - and sometimes it can happen."
Ferguson may now find himself in more trouble with the Football Association after criticising Atkinson's decision-making in the build-up to John Terry's winner.
Ferguson, who branded Alan Wiley "unfit" last month, was adamant that Atkinson's judgement was the kind which lead managers and players to "lose faith in refereeing".
Atkinson awarded a free-kick for Fletcher's challenge on Ashley Cole, and Wes Brown appeared to be impeded as Frank Lampard's delivery was turned into the net by a combination of Terry and Nicolas Anelka.
"Clearly, Darren Fletcher's won the ball - Ashley Cole's never touched and has jumped up in the air - and then (Didier) Drogba's pulled Brown to the ground for the goal," said Ferguson.
"The referee's position to make the decision was absolutely ridiculous - he can't see anything. He's got a Chelsea player (Joe Cole) standing right in front of him - and he doesn't even move.
"It was a bad decision, but there's nothing we can do about it. You lose faith in refereeing sometimes, that's the way the players are talking in there - it was a bad one. That goal should never have been allowed.
"We had great opportunities to get to the edge of the box and some really good chances in and around the box, but we should be finishing it off. We've only ourselves to blame in that respect. But you do need a break - and we never got the break we needed."
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