Manager Sir Alex Ferguson was left shell-shocked at the manner of the 4-0 quarter-final defeat by West Ham after he made a raft of changes.
Some of his fledgling stars were given the chance to shine in a side that was made up of youth and experience, and Anderson was baffled at the way the team caved in.
"I don't think they are quite up to the task everyone thinks they are," said the former United and England full-back on MUTV.
"We changed the whole back five, including the goalkeeper and that is a bit of an ask.
"It has backfired on him (Ferguson) you could see that in his face. He is going to have to really think about the younger lads - they cannot match up to the expectations of this club.
"It was a bit of false dawn we went to Rangers and got a clean sheet. That night the system suited us.
"They had only Kenny Miller up front. West Ham played with two up and that was difficult for us. We conceded some shocking goals.
"It was a hard night and a learning curve for these young lads. It was a bad day especially for the back four."
Another former United star, Lou Macari, joined in the criticism of the team on the in-house TV station.
He said: "They were given an opportunity...'Show us what you are made of, show us what you've got, this is going to be fast and furious'.
"It was not going to be like Rangers where we were attacking all the time. This was West Ham, who were desperate to get into the next round. They have let him (Ferguson) down."
United went into the match on the back of 7-1 victory against Blackburn with Dimitar Berbatov scoring five goals. Blackpool are next up on Saturday.
Macari was keen to see an unchanged side against West Ham.
"I want to see a winning team," he added. "But football is going in a different direction where we read and talk all the time about players getting tired.
"If the ones who had all played on Saturday had played again do not think they would not have been able to play against Blackpool? They would be itching to play.
"Berbatov scored five goals and would have been on all-time high. If he played again scored another couple there would have been more pats on the back. I am not a great believer in chopping and changing."
Source: Manchester Evening News
Source: M.E.N.