The FA Cup has already delivered the biggest shock in its 155-year history this season. Could Saturday's final serve up another one?

On paper, Chelsea beating Manchester City at Wembley wouldn't rank among the competition's most famous upsets. But given the contrasting fortunes of these two teams, it would certainly defy expectations.

Let's break down where both sides stand heading into the showpiece.

Manchester City are chasing a historic domestic treble. They've already lifted the English League Cup, sit second in the Premier League just two points behind Arsenal with two games to play, and have lost only one domestic match since late November. Pep Guardiola's side are in formidable form, even if this iteration doesn't quite match the heights of his greatest City teams.

Chelsea, meanwhile, are in turmoil. Despite spending over $1 billion to assemble a squad that won the Club World Cup less than a year ago, the Blues have sacked two managers since January. Liam Rosenior lasted less than four months before being shown the door in April following seven losses in eight games across all competitions.

Since then, little has improved. Chelsea are winless in seven league matches and look set to miss out on Champions League qualification. They're pinning their hopes on a novice interim coach to end the season on a high and deny Guardiola what would be his 17th major trophy at City and 35th overall.

Calum McFarlane stepped up from Chelsea's academy after Club World Cup-winning boss Enzo Maresca was sacked in January. Now, following Rosenior's exit, he's back in charge for the final. A head-to-head between McFarlane and Guardiola looks like a mismatch of epic proportions—or is it?

Despite his limited experience, McFarlane—a former City academy coach himself—has already produced some standout results. And in a cup final, anything can happen.