The Red Devils took the lead in the 11th minute through Paul Scholes before Simon Davies equalised just before the hour-mark.
United hit the lead when Brede Hangeland netted an own goal with six minutes remaining and then should have been 3-1 up but Nani's penalty was saved by David Stockdale before Hangeland rectified his mistake by powering home a header with a minute left.
FU David Stockdale (gk), Brede Hangeland, Aaron Hughes, Paul Konchesky, John Pantsil, Dickson Etuhu, Danny Murphy (Greening 81'), Damien Duff, Simon Davies (Gera 90'), Bobby Zamora, Clint Dempsey (Dembele 61')
Subs - Pascal Zuberbuhler (gk), Chris Baird, Jonathan Greening (81'), Zoltan Gera (90'), Moussa Dembele (61'), Stephen Kelly, Bjorn Riise
MU Edwin van der Sar (gk), Jonathan Evans, Nemanja Vidic, Patrice Evra, John O'Shea, Paul Scholes, Darren Fletcher, Park Ji-sung (Nani 67'), Antonio Valencia (Giggs 74'), Dimitar Berbatov, Javier Hernandez (Owen 74')