Manchester City preserved their dreams of an unprecedented quadruple by retaining the Carabao Cup – after extra time and on penalties with Raheem Sterling striking the decisive spot-kick – and Maurizio Sarri will hope he has preserved his chances of keeping his job as Chelsea manager.

But that hope has to be qualified. Heavily qualified. The absolutist Sarri adapted, changed his tactics, even finally changed his substitutions and appeared to have listened for a match which could have been – could even still be – his last at Chelsea.

And it worked. Until he was then completely, utterly and shamefully undermined by one of his own players, with goalkeeper Kepa Arrizabalaga flatly refusing to be substituted deep into extra time despite the board being shown and the change being announced. Arrizabalaga had twice gone down injured, having made saves, yet simply would not come off.

It was ridiculous behaviour. David Luiz vainly tried to make him go – Chelsea captain Cesar Azpilicueta failed to intervene – and Sarri erupted on the touchline.

The Italian marched down the tunnel, came back and, extraordinarily, had to be restrained by Antonio Rudiger before the shoot-out while Chelsea’s medical director Paco Biosca also acted as peacemaker.

Biosca attempted to appease Willy Caballero who was stripped, ready to come on but was left humiliated like Sarri. There was logic in bringing on Caballero who is not only a former City goalkeeper – so familiar with the opposition, thereby sowing doubts – but had saved three penalties in the shoot-out for them when they beat Liverpool in the League Cup Final in 2016. But he stood helpless amid the chaos.

Could Arrizabalaga redeem himself? The £72million goalkeeper, a world-record fee for that position, saved from Leroy Sane but it was not enough.

Not when the Spaniard also let a weak effort from Sergio Aguero squirm past him with the striker reacting with shock that he got away with it.