Sir 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-time 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.
While Liverpool fans booed Evra mercilessly throughout, the game itself was free of controversy, with only one yellow card shown.
"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.
"Some of our possession was good. Our movement off the ball was good. I thought we were in the driving seat."
United were without Wayne Rooney, Nani and Phil Jones because of ankle injuries but Ferguson said England defender Rio Ferdinand, who has been missing with a back injury, could return for the league game at home to Stoke City on Tuesday.
"Rio only had one training session prior to the game," added the United manager.
"We couldn't gamble with that. He will train on Sunday and Monday. He could be right for Tuesday."
Liverpool manager Dalglish said his players deserved credit for the way they have bounced back since losing 3-1 at struggling Bolton Wanderers on January 21.
Dalglish raised eyebrows after that dismal reverse with an uncharacteristic public tirade against his squad's performance, accusing them of failing to live up to Liverpool's standards.
Yet the Scot could not have hoped for a more emphatic response in this week's heavyweight games against Manchester City and United.
After booking a place in the League Cup final last Wednesday against City, they produced a spirited performance to overcome United after Park Ji-Sung had cancelled out Daniel Agger's opener for Liverpool.
Dalglish praised the way his squad had reacted after their humiliation at Bolton.
"The week started badly for us at Bolton, but it's a fantastic credit to the players and how much pride they take in the club that they've got themselves back on track," said Dalglish. "They've come out on the right side of two huge cup games."
Although Evra was booed throughout the tie, Dalglish insisted both sets of fans were "magnificent adverts for their clubs".
"There was a wee bit of banter between both fans, which is brilliant because we wouldn't want to take that away, but at the end of the day I thought they were fantastic," said Dalglish.
"The players were a great credit for that as well - none of them tried to do anything other than play football.
"I think both sets of fans were magnificent adverts for their clubs. Both clubs can be very proud of the fans that they have."