McFarlane’s confidence is rooted in January’s Premier League meeting at the Etihad, his first match in senior management, when Chelsea fought back to earn a 1-1 draw. That night, the rookie coach outmanoeuvred Pep Guardiola after the interval, reshaping his team and using his bench to tilt the contest.

City had dominated the first half and led through Tijjani Reijnders, exposing what McFarlane now admits were flaws in Chelsea’s preparation. “The first half was tough, we got the prep wrong,” he said. “They had a lot of control. We didn’t want the game to look the way it did. We had to suffer, we had to run, we had to defend our box really well.”

At the break, McFarlane made a series of bold adjustments that transformed the game and, in his view, offer a template for Wembley. Andrey Santos was introduced into midfield, freeing Enzo Fernández to push higher up the pitch, closer to goal. Cole Palmer shifted from the No. 10 role to the right wing, while full-backs Josh Acheampong and Malo Gusto swapped flanks.

The changes injected aggression and territory into Chelsea’s play. Gusto’s surging runs down the right became a constant outlet, and it was his deep cross that found Fernández at the back post for a stoppage-time equaliser. “We made some changes in the second half to try and shift the momentum and be a bit more aggressive and get more territory,” McFarlane said. “It worked. We got a foothold in the game.”

McFarlane insists the comeback was driven as much by character as by tactics. “I thought it was more down to the players than myself,” he added. “You can give them instructions but there are moments when it’s going to go wrong. The fight that they showed, we worked so hard to get that point.”

The stakes at Wembley are even higher. With Chelsea’s league form collapsing and European qualification via the table all but gone, the FA Cup represents a final route back into continental competition.

There is encouragement on the fitness front. Club captain Reece James and defender Levi Colwill are both in contention after long injury lay-offs, boosting a squad that will need every ounce of resilience and tactical clarity if it is to follow McFarlane’s blueprint and upset the favourites.