David Moyes' side were taken apart by Liverpool as two Steven Gerrard penalties put the visitors two in front before Luis Suarez sealed the win by slotting home past David de Gea late on.
And Rooney, who endured a frustrating afternoon where he saw little of the ball, confessed that the loss at Old Trafford was one of the worst he's suffered during his entire career.
He told MUTV when asked about the mood in the camp after the defeat to their rivals: "It's a nightmare. It's one of the worst days I've ever had in football."
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