I think the last 4 matches have shown this; maybe not in such a blatant manner.
The sending off gave us something to hold on to and we defended really well for, erm 78, mins.
Then the poor sub didn't help to prevent the melt down and that must have taken its toll on player morale; especially if it was low with regards to the manager's ideas etc.
Then the 1/4 final was a big game (with a chance to lead to personal glory), good atmosphere etc so the performance was more intense still.
The following games where there's no real personal glory and, perhaps the thought of "it doesn't matter if we defend well, RM can always balls it up" have seen terribly insipid performances in fixtures that you'd normally hope for more intensity.