BARCELONA, Spain — It was as they were whiling away one of those long, sultry evenings cooped up in the comfortable surroundings of the Hotel Lucerna in Culiacán, Mexico, that Pep Guardiola outlined to Ángel Morales his vision of the perfect goal.

Over the course of their five months in northwest Mexico, Guardiola, who would become the greatest soccer coach of his generation, and Morales, a journeyman playmaker from Argentina, spent hours together, eating, relaxing, talking. A decade later, though, it is that one thought, that purest distillation of Guardiola’s philosophy, that has stayed with Morales.

“He said that his ideal goal was a move that involved every player on the pitch,” he said. “From the goalkeeper to the striker, everyone would touch the ball once, and then, at the end: goal. I told him it was impossible. I am an Argentinean: I liked to touch the ball three, four times, to dribble past someone. But that was what he said. And then, a few years later, when he was at Barcelona, I saw it come to fruition: football just as Pep had said.”

This is an emotional week for Guardiola. On Wednesday, five months into his tenure as manager of Manchester City, he will return here, to Camp Nou, in the Champions League group stage.