For the first 45 minutes, you could be forgiven for questioning whether Chelsea realised a goalless draw suited their opponents. In the absence of Chelsea's usual fast-paced counterattacks – too frequently their initial pass out of defence was wayward – their primary offensive approach was winning set pieces high up the pitch. They put Simon Mignolet under heavy pressure from corners, with Tomas Kalac going close towards the end of the first half, and utilised César Azpilicueta's long throws.

But this was a safety-first approach. José Mourinho was aware of Liverpool's stunning first-half record, and before half-time Chelsea did not concede a shot on target. Chelsea's approach was of more interest than the tactics – once the defensiveness was decided, the type of defensive play itself was obvious. With Luis Suárez up front, Chelsea defended deep to guard against his pace, and defended narrow.

The home side had plenty of possession – the game's top ten most prolific passers were Liverpool's ten starting outfielders – but little incision, with a midfield trio of Steven Gerrard, Lucas Leiva and Joe Allen meaning Coutinho had to play higher up. The Brazilian and Raheem Sterling were wide in a 4-1-4-1. Both drifted inside but this narrowed Liverpool, who were reluctant to push the full-backs to the byline for fear of opening up the pitch to Chelsea counter-attacks.

Chelsea's opener, courtesy of Gerrard's slip and Demba Ba's composed finish, changed the scoreline, but did not alter the tactical battle. Chelsea's initial approach was certainly to get to half-time at 0-0, but they would have been forced to become more adventurous in the second half, potentially playing into the hands of Liverpool's direct attackers. Instead, their one-goal advantage ensured they were able to continue playing extremely deep.

Inevitably, Rodgers changed shape – from the 4-1-4-1 to a midfield diamond, with Daniel Sturridge on for Lucas and used up front alongside Suárez, with Sterling now at the top of the diamond. It did not cause Chelsea's defence significant problems, with the forwards crowded out and midfielders like Allen, Gerrard and Coutinho – now much deeper – given time and space.

Allen's play lacks penetration but he at least distributed the ball quickly, but Coutinho overhit passes and Gerrard attempted no fewer than eight increasingly optimistic second-half shots. There's a fine line between leading by example and attempting to accomplish everything solo to the detriment of overall team play – and the performance of Liverpool's captain, in his desperation to compensate for his error, strayed into the latter.

As Liverpool increasingly threw players forward, counterattacking opportunities presented themselves – André Schürrle and Mohamed Salah found life difficult, but substitute Willian continually motored forward on the break, eventually combining with fellow sub Fernando Torres for the clinching goal in stoppage time.

Mourinho's tactical blueprint was followed to the letter, but it's hardly the first time he's parked the bus. The real story was Liverpool's lack of a clear gameplan against that approach – Rodgers' tactical flexibility has been a crucial part of Liverpool's title charge, but he had no answer for this particular question. The only logical explanation is that Rodgers did not expect his opponents to play so defensively throughout a game they needed to win. But never underestimate Mourinho's caution.