The 22-year-old made his first appearance since December 28, when he was still a Newcastle player, after a thigh problem as a 74th-minute substitute. But Dalglish has warned not to expect too much too soon from the England international, who had scored 11 Barclays Premier League goals prior to his injury.
The Scot said: "He is a good guy. He is not someone who thinks he is superior to anyone else, he just loves playing football and wants to be part and parcel of the club. We have to temper his enthusiasm a bit. He is only a young lad, he is going to be big player for this club."
Dirk Kuyt scored his first Liverpool hat-trick, and the first by a Reds player against United since Peter Beardsley in September 1990, to render Javier Hernandez's late header irrelevant.
"To score a hat-trick against United is the best feeling ever," said the Holland international. "We showed that we can compete against the best but we need to compete against the other sides."
Dalglish, however, accepts they still have some work to do before they can match United in challenging for the title.
The win lifted the Reds back up to sixth, but they are 18 points behind their arch-rivals who lead the Barclays Premier League by three points from Arsenal.
"Manchester United are a benchmark for everyone, are they not still top? There is no-one who would rather be in their own position than United's.
"The closer you get to the top the more difficult it is to close the gap. Moving from 20th to sixth is not as big a problem as moving from two to one so the higher you go the more difficult the step up is.
"United are a great benchmark but our season is not finished. We got our reward for the victory in three points in the league, but we just want to keep going and get as many as we possibly can."
Source: PA
Source: PA