Alex Ferguson labelled Manchester United's 2-1 FA Cup defeat by Liverpool as "sickening" after the champions dominated the tie before being sunk by a late Dirk Kuyt goal.
Kuyt's dramatic 88th-minute winner dumped record 11-times winners United out of the FA Cup and left Liverpool and manager Kenny Dalglish one step closer to a repeat of their 2001 League Cup and FA Cup double.
The fourth-round tie was the first time the bitter rivals had met since Liverpool striker Luis Suarez was hit with an eight-game ban for racially abusing United's France defender Patrice Evra in a league game on October 15.
But the tie appeared to pass off without major incident after Dalglish and United counterpart Ferguson appealed for calm in the build-up to the game. "The players showed great respect for each other," said Ferguson afterwards.
"There was not a bad tackle in the game. It was played in a good spirit. We are pleased with that. To lose is a real sickening blow. We dominated the game in terms of possession. We did very well in that respect. But to lose the game is hard to believe."