Berba struck in the second half after Wayne Rooney had fired United into the lead after 23 minutes following a superb pass by substitute Ryan Giggs.
It was no more than United deserved, and Berbatov then took charge with two goals in the second half to put United totally in control.
The Bulgarian volleyed his first goal for United after 55 minutes, but barely moved in celebration of the strike.
Berbatov then added his second and United's third in the 79th minute to cash on a failed clearance following a Cristiano Ronaldo cross.
Giggs was on after only 15 minutes when Paul Scholes appeared to jar his knee and was stretchered off. Scholes could now face a lengthy lay-off, and manager Sir Alex Ferguson confirmed: "He's got knee ligament damage. We don't know how serious it is obviously.
"We'll have it assessed as soon as we get home."
Ferguson had sprung a major selection surprise by handing 18-year-old Brazilian Rafael Da Silva his European debut. With captain Gary Neville left at home to nurse a groin strain, Ferguson had been expected to select Wes Brown at right-back but instead plumped for Da Silva, who impressed during last week's Carling Cup win over Middlesbrough.
Man Utd: Van der Sar, Evra, Ferdinand, Ronaldo, Berbatov, Rooney, Vidic, Nani, Scholes, Rafael, O'Shea.