C helsea fared well as underdogs in their most recent outing in a final. They surprised Paris Saint-Germain in last summer’s Club World Cup, racing into an unassailable 3-0 lead by half-time and disrupting the European champions thanks to a clever tactical approach from Enzo Maresca. Perhaps there will be more of the same at Wembley. Chelsea have form when it comes to upsetting the odds in a big game, although the one problem with bringing up the PSG win before Saturday afternoon’s FA Cup final against Manchester City is that the challenge of coming up with a plan smart enough to beat Pep Guardiola is no longer Maresca’s responsibility. The subplot is that it is quite possibly a clash between Maresca’s past and his future. For Chelsea, the moment when a season of promise began its descent into chaos is, from their perspective, when their former head coach began to act like a man who wanted to leave.…