The 24-year-old is simply relieved the saga with Arsenal is over after spending much of the summer in limbo hoping the move would happen.
"The last months I've been under a lot of pressure," he admitted.
"Mentally it's really tiring, but it finally happened and I'm very happy to be back at Barca.
"It is partly my fault that it has been so complicated, for having left. Not in my wildest dreams had I imagined that one day I would play for the Barca first team.
"Not as a child, nor playing with Arsenal had I thought I'd live a day like Monday."