Manchester United legend Bryan Robson was shocked by their performance in defeat to Champions League opponents Olympiacos last week.
The former skipper watched on in horror as David Moyes' new breed slumped to a disappointing 2-0 defeat in the Champions League first leg.
"The performance in Athens was as poor as it gets for a Manchester United team. It was awful," Robson told the Manchester Evening News.
"They can't blame having a new manager or anything like that. The truth is the players just did not perform and they have to respond now.
"They owe everybody - the fans, the manager, the club and themselves a big performance against Olympiakos at Old Trafford."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball