Berbatov says United can challenge Man City and Liverpool for the Premier League title if they make the correct signings.
He told Betfair: "It's been a challenging few years, but the fact remains that United need to be challenging for the title. They need to improve again to challenge Man City and Liverpool next season, but they can do it.
"Every season is different and has its unique ups and downs, the teams you expect don't always end up doing well, but with United you always expect them to be title contenders, especially if they make some signings."
"There will always be doubters, but overall people will realise managers need time to build. There are obstacles, of course, but in the future things can improve, and Ole has shown that.
"It will be more difficult now with the Champions League, and you will still get criticism next year when you lose, but for now we should be happy with the work he has done.
"I think the players love him, and that's shown by how they've played."