Manchester United boss Sir Alex Ferguson admits their derby humiliation was a black mark on the club.

Ferguson admitted the score would cast a shadow over the club for years, but insisted that his players would respond.

He said: "There is no progress in life without failure. For one thing, it means you think about how you got to the top in the first place. It's another day in our history, one that will be talked about for a long time to come.

"We have certainly had better days, but there is no time for tears. Our players are eager not to make that kind of mistake again, or at least not for a very long time."