I'd say we had a number of players who outdid themselves playing expansive and in some cases new and unfamiliar roles -- different than last season.
Fernandinho has always been capable but this year as the MF "glue" he performed amazingly well -- the most unsung role on the team. Delph (and Zinchenko) filling in at LB were extraordinary. Ederson playing "CB"/sweeper and (yesterday for five seconds) holding mid :). Otamendi, defending and distributing; Augero's closing down, along with a number of others.
Didn't Pep once say he'd field 11 midfielders if he could? What he did so often is field 11 FOOTBALLERS. How often did someone's absence really hurt us this year? It's ironic that Mourinho has all year struggled to find a spot for role-players, whereas we never really did, because everyone's "role" is so much greater than the sport's traditional concept of a particular position.
That takes skill, confidence, cohesiveness and belief, and Pep has filled the players with it all.