Sesko has eight goals in his last 11 appearances in all competitions for United.
Berbatov told manutd.com: "He has all the qualities right now, everything in this moment is working well with him.
"I hope it continues in this way. I think, right now, things are getting good for him and things are working out slowly for him.
"But I prefer it like this. I want him to slowly, but surely, get that confidence, get the goals, which they are both connected. When you get the goals, you get confidence.
"He is finding his position into the team but, even if he is on the bench, the sign of him coming onto the pitch now brings that threat and that fear factor in the opposition and it brings the goals.
"It's very good, seeing him getting off the bench, sometimes scoring goals. Starting and scoring goals. To be honest, I don't care what type of goals he scores, as long as the ball hits the back of the net.
"Until you bring that confidence in, you know, when you step onto the pitch, that goals are guaranteed."