But Mbu is determined to put things right for Sunday’s home clash against Doncaster.
Mbu said: “The players know they can’t afford to have any more of those games, where we get beaten that heavily.
“It was an off day for us, and I hope we don’t have too many more off days.”
Doncaster travel to the capital on the back of three successive wins, having seen off Rochdale, Thatto Heath and South Wales over recent weeks.
Chris Spurr (hamstring) is unlikely to feature this week but prop Jamie Bovill, who returns from a one-match suspension, will boost the Dons’ ranks for the trip south.