The England international, who spent nearly two decades progressing through Old Trafford’s ranks, found himself on the outskirts after the Portuguese coach’s arrival.
By January, he was surprisingly loaned to Aston Villa in a mid-season move that helped him regain his form.
“We are very happy because a player of great quality is coming, at a great age to come to Barça with extraordinary motivation. Personally, I’ve seen how excited he is to come to Barca," he told reporters.
"One of his virtues is that he is sincere. His dream was to play for Manchester United for the rest of his life. He arrived at the age of seven and was born there with an interesting life. He wanted to be a ‘One club man’. It’s nice for a player to say this with all the sincerity."
Laporta continued: "But when a situation arises in his life that he did not expect, the team he had always liked is Barca. He had faced us and had Barça on the radar.
“He was loaned to Aston Villa so that it could be seen that he is the best player ever, the best in England and he says that his maximum motivation is to win the Champions League with Barca and the World Cup with England.
"We have him very motivated. He came in strong as a rock, he’s very excited, he’s entered well with his teammates and I’m very happy because two years ago he beat us in the Europa League. He made the difference in the tie and that’s why I’m very happy that he came.”