Dalglish's return to English football was shaped by two key decisions from World Cup final referee Howard Webb. The penalty award, and the red card shown to Steven Gerrard.
"The penalty is a joke," said Dalglish.
"I have seen the replay and unless they have changed the rules it is no penalty.
"The other one, I cannot see that as a red card either.
"In the dressing room before the game someone said to me the game's not changed that much.
"I said 'I thought it was a non-contact sport'. Maybe I was right."
Dalglish has more important matters to occupy his mind though, leaving Sir Alex Ferguson with the stage to outline a differing view of Daniel Agger's challenge on Dimitar Berbatov inside the opening 30 seconds and Gerrard's subsequent lunge on Michael Carrick.
"It was a penalty," he argued.
"Dimitar says he was definitely clipped. The replay shows he slightly touched him but the momentum is enough to bring the player down.
"There is no reason for him to go down anyway. He is not that kind of player.
"He is on the by-line, he is in the penalty box. I think it was right.
"As for the sending off, there was no doubt.
"It was two-footed and he was off the ground.
"Steven Gerrard is not that type of player but it was a reckless challenge. I don't think he left the referee with any option."
As Ryan Giggs tucked home the penalty in nerveless fashion, United had the advantage even before Gerrard's exit.
And, while Liverpool were never put to the sword as the home fans had been hoping for, United always had the edge, even though it took an excellent save from Tomasz Kuszczak to deny Fabio Aurelio near the end.
"It is amazing it was only 1-0," observed Ferguson.
"But sometimes, when a team is down to 10 men, you get that kind of resilient attitude.
"We should have put it to bed in the second half and it could have been three or four.
"But anything can happen at 1-0. The FA Cup is riddled with it.
"Newcastle were reasonably comfortable against Stevenage yesterday, then someone shoots from 25 yards and it goes in off the defender's head. The whole game changes.
"Fortunately, we didn't do anything stupid today that would have caused us embarrassment."
It allowed United to advance into a fourth-round meeting with League One outfit Southampton in three weeks' time, when Ferguson would expect to have Wayne Rooney (ankle), Nemanja Vidic (leg) and Edwin van der Sar (virus) back at full throttle.
All three missed out this afternoon, although Ferguson does not seem worried about any of them.
"Wayne came out for training on Friday and we thought he would make today," said Ferguson.
"But he just felt it again. At that point, we said no. There was no point.
"Vidic got a knock in training. He will be okay for Tottenham next Sunday. Edwin will maybe be another week or so."