The United hero has defended his former teammate's dip in form and, whilst he believes Ronaldo can dig himself out of it in, he should not take all the blame and the other players need to 'produce more for him'.
Speaking to Betfair, the Bulgarian who played for United between 2008 and 2012, said: "When teams have a bad result the star players always end up with the blame, and at the minute with Manchester Untied, that's Cristiano Ronaldo.
"At the moment he's got just one goal in ten games and that seems problematic for everybody, but not for me.
"There are eleven players on the pitch and the blame should be shared. Ronaldo is an icon in the world of football and people need to remember that he's 37.
"So, from time to time he is allowed to have a couple of bad games. But I don't think that is the problem here. Overall, as a team when they have a good game they have to follow that up.
"I think Ronaldo is doing enough for United, obviously people will look for more because of the standards that he sets. There will always be people questioning him when he has a bad match, and they are taking advantage of that now. People need to consider his age, how he plays, his position and how the team plays.
"People need to be realistic with him and they need to know that it's totally different when you're 37 to being 27. He is going to have moments when he needs his teammates to produce more for him, that's normal in football.
"Ronaldo is a total professional and he will speak to the manager and he will want to produce more. Everybody in the United team needs to produce more, the standards should be a lot higher than they are.
"Ronaldo is also a realistic guy, he will know that his performances aren't where he wants them to be, even though he's older and his game is totally different, he sets very high standards. I don't think that needs explaining to him.
"Everything that he has achieved in football isn't because of luck, he knows what he is doing, and he will know that he will need to produce more at the moment and trust me, that will drive him forward. People need to get off his back and let him get on with it."
Berbatov also gave his view on United bringing in big-name players in to assist Ronaldo with the Red Devils next season.
United have shown interest in signing Erling Haaland to bolster their attacking options, and the club legend believes Rangnick does need to 'start dreaming' the star-studded strike force can become a reality.
"I saw the video going around social media of Ralf Rangnick laughing off Erling Haaland signing for United," he said. "He told a fan that they 'must be dreaming' about signing him."
"Maybe that's a sign that they can't afford him or it's not possible for him to move to the club at this moment in time when they aren't producing good enough football to get his interest, maybe that's what he meant.
"For me they need to go back to those high standards of performance that they used to set, so that they can attract big players.
"Everybody wants him in summer and maybe Rangnick was being realistic."
The former striker went on to state that the interim boss needs to be mindful of the way he discusses transfer targets in public should he want to improve United's squad following the German's comments on Saturday.
"It's not a great look though, and in this day and age you have to be careful because you can end up in a moment where you need to explain yourself," he added.
"You must be mad to not want a player like Haaland in your team, so maybe Ralf Rangnick should start dreaming."