The 31-year-old scored 57 goals in 149 games during four years at Old Trafford after Sir Alex Ferguson prised the Bulgarian away from Tottenham.
Despite winning a league title and the Premier League's leading goalscorer award, Berbatov feels the need to defend himself against claims that he didn't try hard enough as a United player.
"I left Manchester United with my head held very high," the 31-year-old told The Sun.
"I gave 100 per cent and no one could doubt my performances, especially when you compare how many minutes I actually played.
"I was the Premier League's top goalscorer in 2010-11 and never wanted to be on the bench.
"Perhaps I needed to play more but I always accepted the manager's orders. I never considered myself to be a star - only a forward working for the team."With three goals in five starts for Fulham, Berbatov is settling in quickly in west London.
"The Fulham directors spoke directly with me to explain their ambitions and how I fitted in with those plans," added Berbatov.
"That was the key and also the fact that my family are happy in England. I received another proposition from Fiorentina but my preference was always to stay in the Premier League."