Ole Gunnar Solskjaer admitted his Manchester United side let themselves down after Burnley condemned them to a shock defeat.
Goals from Chris Wood and Jay Rodriguez in either half gave the Clarets a first win at Old Trafford for 58 years and dented United’s hopes of a top-four spot.
United remain fifth, six points adrift of fourth-placed Chelsea , with under pressure Solskjaer conceding his side were well below the standard expected of the 20-time champions.
“For me, the most important thing is we have to perform on the pitch,” said Solskjaer. “Tonight wasn’t good enough for a Manchester United team.
“The boys have given everything they’ve got, but they’re experiencing this period for the first time in their lives.
“When you’re at Manchester United, you’re playing at the biggest and best club in the world. Some of them have played 10, 12, 15 games and it’s not easy for them.
“I’m going to back them and help them get through this. We can’t do anything but hold our hands up and say it’s not good enough.”
There were anti-Glazer chants from furious United fans and renewed calls from the stands for executive vice-chairman Ed Woodward to be sacked.
Former United defender Ferdinand, in his role as a pundit for BT Sport, did not hold back in his criticism of the his old club.
“I’m sitting up here and if I’m honest, I’m embarrassed,” said Ferdinand. “Fans are walking out after 84 minutes. It’s an embarrassment.
“It’s embarrassing to be here. The way the team is. Not just the way the team perform but I don’t see what is coming next. You don’t see a pathway.
“Around £600million has been spent on this squad, and on what?
“I don’t see it out there. I don’t see that the money, the recruitment, what has been bought.
“There’s nothing there that suggests to me that this is going to be something that is laying down the foundations for the future.”