The build-up to Manchester City's Premier League clash was all about managers Pep Guardiola and Antonio Conte, but the big talking point of the match was an incident involving Sergio Aguero and David Luiz.
On the half-hour mark, Cesar Azpilicueta miscued a pass to teammate Luiz and Aguero pounced, only to collide into Luiz and go down as he tried to sprint past the Brazil defender and go clean through on goal.
City's players and fans inside the Etihad Stadium appealed vehemently to referee Anthony Taylor, but the official let play continue as Luiz nonchalantly passed the ball out of defence to start a Chelsea counter-attack.