"It was shambolic ... so bad," Scholes told BT Sport after United were sunk by a first-half penalty from Daniel Sturridge and a 73rd-minute goal by Roberto Firmino. "Tonight was a disaster.
"Liverpool had a way of playing. United? I didn't have a clue what they were trying to do.
"United have spent 250 million pounds (under manager Louis van Gaal) ... they are sixth in the Premier League and have ended up in the Europa League," added former England midfielder Scholes.
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"They should be competing with Barcelona, Real Madrid and Bayern Munich (in the Champions League). United didn't need a new philosophy, they had one for 20-odd years that worked," he added in reference to the 38 major trophies won under Alex Ferguson before he retired in 2013.
Ferdinand, a former United and England team mate of Scholes, was equally scathing of Van Gaal's side.
"The fairytale has gone," he said. "The players he has let go, Angel Di Maria, Nani, Patrice Evra, Javier Hernandez, Shinji Kagawa, Danny Welbeck, Rafael, Darren Fletcher, are they worse than the players out there?
"They are better than that team out there today, that's the problem."
Van Gaal, who has been under fire for most of the season because of United's poor results and a perceived lack of entertaining football, said Liverpool deserved their victory.
"They played very good in the first half and we could not cope with their pressure," the Dutchman added.
"(United goalkeeper) David De Gea was fantastic but we conceded a cheap penalty and in the second half we changed the shape. We had much more contribution to the game but didn't create enough."
(Writing by Tony Jimenez; Editing by Ian Ransom)
