Ronnie: Barca were my first choice
The Red Devils lost out in the summer`s biggest transfer saga when Barcelona landed the multi-talented Brazilian on Saturday.
United were quick to claim that although disappointed, the Samba star`s decision to move to Spain will not harm them.
Red Devils chief executive Peter Kenyon hinted that the player did not have the required quality and desire to play for United, but Ronaldinho has hit back by saying he has nothing to prove to the Old Trafford hierarchy.
"I haven't got anything to prove to the English," the 23-year-old said.
"My first option was always to play in Spain. There were a lot of reasons but the most important one is that it is where the best championship in the world is.
"I'm grateful (Sir) Alex Ferguson was so interested in me but in life you have to make a lot of important decisions.
"I've opted for Barca and I hope I haven't made a mistake."
The World Cup winner claims he could still be seen in The Premiership at some point in the future.
He added: "I'm young and there's a lot of football left for me to play. Who knows if one day I'll end up in The Premiership?"
United meet Barca in a friendly on August 3, and Ronaldinho is ready to play if given the go-ahead.
"If I take part in it, I'll be calm and won't feel any kind of pressure," he concluded.
