The Reds fell at the third-round hurdle as a late goal from Benjamin Sesko was not enough to cancel out strikes from Brajan Gruda and former United man Danny Welbeck in the 2-1 defeat.
Fletcher answered questions on how the squad bounce back from this setback, aims for the rest of the season and gave his assessment of the players in his post-match press conference.
Here's everything our interim head coach had to say...
What's the mood, and what's the atmosphere been like in the changing room after that?
"Well, bitterly disappointed because we're out of the FA Cup.