Sir Alex Ferguson slammed referee Martin Atkinson's performance as Manchester United's Treble dreams went up in smoke on Saturday.United had the better of the chances against Portsmouth but Sulley Muntari's penalty proved the difference as the visitors snatched a 1-0 win in a thrilling FA Cup quarter-final at Old Trafford.

Muntari faced Rio Ferdinand in the United goal after Tomasz Kuszczak, who replaced the injured Edwin van der Sar at half-time, was shown a red card for bringing down Milan Baros.

But it was a penalty that was not given that incensed Ferguson, with Cristiano Ronaldo appearing to have been fouled by Sylvain Distin early in the match.

"It's absolutely ridiculous," Ferguson told MUTV. "I cannot explain it. Managers get sacked because of things like that and he's going to referee a game next week."

The United boss, who also felt Atkinson was too lenient on Portsmouth fouls, laid the blame at the door of referees' chief Keith Hackett.

"He's not doing his job properly and he needs to be assessed," said Ferguson. "I'm assessed as a manager, players are assessed, referees should be assessed properly by the right people. That performance should not be accepted by our game."

Ferguson, however, had no complaints about the spot-kick awarded to Pompey and red card for Kuszczak.

"It was a penalty kick," he said. "The boy Kuszczak had to do his best but I'd rather he let him score and then we'd still have 11 men on the pitch."

The United boss called for a response from his team when they resume their hunt for the Premier League title against Derby next weekend.

"It has to have an impact, the impact is we've got to do something about it," he added. "The determination, the energy from their team showed us something."

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