Bale, who made a name around Europe after scoring a hat-trick at the San Siro in October, is in line to face AC Milan in the Champions League at White Hart Lane on Wednesday night, with Spurs holding a 1-0 advantage, after recovering from injury.
Harry Redknapp's side are again pushing for a top-four place this season and United striker Berbatov is delighted to see his old club doing so well.
"Their position doesn't surprise me. When I was there I was aware of the young talent that is now their major asset - players like Aaron Lennon and Gareth Bale have matured and become great players, '' Berbatov told United's website.
"When I was there Bale was a talented teenager, now he's one of the best players in the world. I saw he had potential. He trained hard and was pushing to be involved.
"I'm glad they kept faith in him - other teams were interested in buying him - now they're reaping the rewards.''