LONDON — One year ago, F.C. Barcelona suffered a mighty tremor, one that shook the locker room and the fans. Tito Vilanova died of cancer at the age of 45. He was the man who assisted Pep Guardiola as coach before seamlessly replacing him for one season.

Every player lost something of himself in that month. Barça had a competent man, the Argentine Gerardo Martino, in charge of the team when Vilanova died, and the club was still fighting for the Spanish league title. But Josep Maria Bartomeu, the interim president of the board, already knew the identity of the next coach.

It had to be a man from Barcelona’s culture, and it could not be Guardiola, who was by then tied to Bayern Munich. The new coach was an old colleague of Guardiola’s: Luis Enrique.

Apart from the coach, the other priority for Bartomeu was to keep Lionel Messi with the team and, just as important, to bring back the smile to Barcelona’s — and the world’s — best player.