Rakitic, now with Hajduk Split, says Barca's players became "bored" with their superiority over rival teams across Europe.
"With all the love and respect I have for all the teams, I didn't win more titles at Blaugrana because I was bored and thinking about things other than football," he recalled.
"With Roma and Liverpool we made a mistake, but I'm convinced that the boredom of feeling too superior affected us. If you don't give your all, you don't win. If we had stayed hungry, we would have won one or two more Champions Leagues."
Rakitic also returned to the tension with former Sevilla coach Quique Sanchez Flores.
"It's clear that I didn't understand him, I didn't agree with his words. It's not that I didn't support him, but I didn't agree with how things were going. I don't think about myself, but about the group and Sevilla. If there's someone who sees it differently, I don't agree, I wasn't wrong because I didn't like the interviews he gave.
"I made the right decision. How do I see the team now? We'll trust, I want to be very positive, believe in the coach and his staff. We need a bit of luck, there have been good games, I want to be positive for what's to come."