Four days after squandering supremacy in the Mancunian derby, Manchester City somehow managed to do it again in this Champions League tie against Liverpool. Leading at half time, looking confident and in control, playing with pace and panache, they ended up losing, their fans obliged to listen to the visiting hordes from Merseyside serenading the victory that took their side to the semi-final of Europe’s senior competition.

After three defeats in a week, never mind a game of two halves, for Pep Guardiola this is rapidly turning into a season of two halves.

Mohamed Salah’s goal changed everything here, turning City’s expedition up Mont Blanc into an Everest of a climb, with the oxygen jettisoned at base camp. Needing a further four goals in an increasingly exhausted, desperate, last half-hour, they had nowhere to go. With Liverpool harrying and chasing, the inevitable came into view when Roberto Firminho added a second.

All that was left for the City supporters was to join their manager in directing bitter blame at the referee. But there was something different here from Saturday’s surrender to Manchester United. To suggest that City somehow imploded is to misrepresent what happened, to underplay their opponents’ defensive purpose.

Because this was a magnificent performance by Liverpool, a titanic, backs-to-the-wall exhibition of stubborn defiance from a side widely reckoned to be incapable of doing anything to stop the opposition.