The visitors won at the Theatre of Dreams for the first time since 1980, courtesy of Joao Moutinho's 82nd-minute winner.
Ralf spoke to MUTV, Sky Sports, the BBC and at his press conference following the setback and could not hide his frustration...
POOR PERFORMANCE
"We didn't play well at all, neither individually nor collectively. In the first half, we had big problems to keep them away from our box and from our goal. In the second half, we changed to a different formation, with a back three, and we had more control on the game.