In the summer of 2018, with a Premier League title and all kinds of records in the bag, the question that naturally presented itself to Pep Guardiola was this: how do you improve on perfect?
Never before had a side in the English top flight reached 100 points in a single season, or for that matter scored over 100 goals. It was not just a quantitative excellence either; there were few apparent upgrades in any position, and yet it was necessary to make some signings, even if only for the sake of warding off the regression that can come from stasis.