Portsmouth won 1-0 at Old Trafford, when they were awarded a 77th minute spot kick as Milan Baros was felled by Tomasz Kuszczak, who was sent off before Sulley Muntari fired home the winner.

However, Ferguson was furious with Atkinson's decision to turn down a seventh minute penalty for United, when Cristiano Ronaldo was clearly fouled by Sylvain Distin.

The United boss was also angry with the tough-tackling display of Pompey midfielder Lassana Diarra, who was only cautioned.

"I think this game was decided when Ronaldo's penalty was refused," the Scotsman told Sky Sports.

"I think that gave them great confidence to hang on knowing the referee was on their side and Diarra's had, I don't know, eight-nine fouls in the match, it's incredible.

"I have got to agree with Arsene Wenger that someone's going to get a serious injury in our game.

"I know that he's had one himself and it's not a nice time to maybe talk about that but the treatment Ronaldo's getting, I'm worried about that."

Ferguson has been in continuous refereeing criticizm this season, and was even banned by the FA after blasting Mark Clattenburg during the 1-0 defeat at Bolton last year.

However, the veteran coach admitted that the referee's performance had nothing to do with the number of chances squandered by his players.

"But we didn't need to worry about the referee in terms of the chances that we had," he added.

Apart from Patrice Evra's shot against the post, United had efforts from Carlos Tevez and Michael Carrick cleared off the line by Portsmouth.