Victory provided United with a healthy advantage over Arsenal and Chelsea, who meet at the Emirates Stadium today, and nearest challengers Manchester City, who have played two games more.
And while Wayne Rooney's wait for a goal in open play goes on, Berbatov continues to fill the void superbly.
The much-criticised Bulgarian is now on 13 for the season, although his second did require a massive deflection off Anton Ferdinand after he had provided United with a fourth-minute opener in a one-sided contest.
It was almost beyond comprehension that United were not out of sight by half-time. Not only had they scored an early goal, they had also struck the woodwork on two occasions, Rooney had twice gone close to grabbing that elusive first goal in open play since March, and both Berbatov and Ryan Giggs had threatened terror at every turn.
In response, under-strength Sunderland failed to muster a single shot. Yet visiting manager Steve Bruce will have remained hopeful of if not gaining that long-awaited win over his old boss, at least not returning to Wearside empty-handed despite missing seven key men.
Berbatov had broken the deadlock in such simple fashion. Giggs's driving run through the Sunderland midfield caused the visitors a major headache. When the veteran laid off a pass to Rooney, Berbatov was in space at the far post.
All his strike partner had to do was find him, which he did with a superb chipped cross which the Bulgarian powered home.
On his previous start a month ago, Berbatov scored five and United bagged seven. For a while it seemed a repeat was on the cards. Rooney floated an excellent chip narrowly wide, Berbatov thudded a shot against a post, and Anderson weaved his way into space on the edge of the area and curled a shot that beat Craig Gordon but crashed down off the bar.
The Scotland goalkeeper was relieved to see another effort from Berbatov flash into the side-netting, then saved with his feet as Giggs threatened.
Amid all this, Rooney had let fly from the edge of the area and had Gordon scrambling to make the save.
Yet, as Phil Dowd blew his whistle to end the punishment, Sunderland had still only conceded once, knowing United had shown enough weakness earlier in the season to remain vulnerable.
United's goal came under threat at the start of the second period but any home worries were brought to an end when United benefited from a slice of luck they should not have needed.
With Rooney's overlapping run offering Berbatov space after Anderson had picked out the Bulgarian with a pass he delivered while appearing to look the other way, a shot was lined up for the right corner of Gordon's goal.
The goalkeeper committed, Berbatov's effort then struck Anton Ferdinand, whose last-minute own goal in the corresponding fixture last year cost his side their first Old Trafford win since 1968.
This time, it was not so costly but the outcome was just the same as the goal doubled United's advantage and they cruised to all three points.