United have already won the Carling Cup this season
Fulham manager Roy Hodgson has backed Manchester United to win the quintuple after seeing his side thrashed 4-0 by the Red Devils in the FA Cup.
The Premier League leaders are through to the semi-finals of the FA Cup having already won the Club World Cup and Carling Cup.
"Of course it is possible for United to win the lot," said Hodgson. "I wouldn't bet against them.
"The most difficult test could come in the Champions League."
United face Inter Milan at Old Trafford in the second leg of their last 16 tie on Wednesday having secured a 0-0 draw in the first leg in the San Siro.
United dominated that game, creating numerous chances, but were unable to get an important away goal that would make their task easier in Manchester.
Their opponents Inter are managed by Jose Mourinho, who masterminded Porto's defeat of United at the same stage of the competition in 2004, where a last-minute goal from Costinha prompted him to sprint from the dug-out to join his players' celebrations.
United are in superb form though, having extended their unbeaten run in all competitions to 15 games with victory at Fulham on Saturday evening thanks to two goals from Carlos Tevez, and a goal apiece from Wayne Rooney and Ji-Sung Park.
During this run they have opened up a seven point lead at the top of the Premier League, with a game in hand over their nearest rivals, while last Sunday they overcame Tottenham 4-1 on penalties to lift the Carling Cup.
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