Victory provided United with a healthy advantage over Arsenal and Chelsea, who meet at the Emirates Stadium on Monday night, 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 put United in front with a fourth-minute header 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 through Berbatov and Anderson, Wayne Rooney had twice come close to grabbing that elusive first goal in open play since March.
In response, under-strength Sunderland failed to muster a single shot in the first half. Steed Malbranque and Asamoah Gyan tried their luck soon after the restart before Boudewijn Zenden finally managed a shot on target for the Black Cats near the end.
Source: PA