The Bulgarian hitman became only the fourth player in Premier League history to achieve the feat as the Red Devils moved to the top of the table.
Berbatov's haul brought his 10-game run without a goal to a shuddering halt and saw him join former United striker Andy Cole, Alan Shearer and Jermain Defoe in the elite group to hit five.
The shocked former Spurs striker said: "I can't believe I scored five in a game but it happened. I have scored that many before but it was a long time ago back home in Bulgaria.
"Today I did it in the Premier League. To stand next to people like Cole and Shearer is a great honour."
It took Berbatov just 71 seconds to open his account and he said: "The first was the most important. It gives you confidence to play.
"As a striker, people do tend only to look at the goals you score. I am more concerned with how I play but today was all about goals for me."
Nani and Park Ji-sung also found the net in United's biggest win since beating AS Roma by the same score in the Champions League in 2007.
While Berbatov grabbed all the headlines, Wayne Rooney is still searching for his first goal in open play since September. But his manager was quick to praise both strikers.
Sir Ales said: "Dimitar and Wayne were fantastic today. They were a constant threat - their movement, passing and one-twos. It was a top performance by both of them."
Christopher Samba netted a consolation near the end but Rovers manager Sam Allardyce admitted his side had been badly beaten.
He said: "This won't be any easy one for us to forget. We were completely outplayed and have just gone under."
