Before: An amazing talent.
After: An unstoppable juggernaut and one of the best players in history.
Undoubtedly Guardiola's biggest success has been the way in which he has extracted match-winning performances week in and week out from Lionel Messi.
Even before Guardiola's arrival at the club, Messi was heralded as one of the best players in the world.
The way he cut in from the right wing made defenders quake in their boots.
However, Guardiola removed him from his position of comfort and thrust him into a new role especially made for a player of his talents.
He made Messi a "false 9"—the lone striker who plays deep, sometimes even in midfield.
Before playing in this new role, Messi scored at a steady rate, made a fair few assists and boggled minds with his runs.
After his shift, every statistic of his has skyrocketed to astonishing figures. He now averages more than 40 goals a season for the past three seasons, not to mention the 20 or so assists that he makes as well.
Another consequence of this singularly brilliant move is that Messi can aid the midfielders in providing the creative impetus needed for the team to score.
When he drops deep, his passing and vision—which are both comparable to Xavi's—becomes more prominent, and defenders get confused about whom to mark.
When people say that Guardiola has an easy job—he just has to ask his players to pass the ball to Messi—they couldn't be more wrong.
Guardiola's insistence to move Messi to the center of the pitch is what has made both Barcelona and Messi the forces that they are. And it is the move that has acted as a catalyst to Messi's entry into football folklore.