How long Maurizio Sarri’s tenure at Stamford Bridge may last is anyone’s guess. But based on Monday night’s evidence, his job is hanging by the thinnest of threads.

Even Sarri’s most fervent supporters have to question what they’re seeing after Chelsea tamely exited the FA Cup with a 2-0 defeat at home to a Manchester United side that have been resurrected by their own managerial change.

Ander Herrera scored the opener for United with Paul Pogba adding a second in the first half to end the run of the reigning holders of the FA Cup.

For Sarri’s critics, this was another match to heap pressure on him. Once again, his side were sterile in possession, looked unorganised in defence, and yet again, the manager failed to attempt to fix the situation with any tactical tweaks.

His substitutions were even more predictable than the patterns of play on the pitch — Ross Barkley for an ineffective Mateo Kovacic, Willian for an ineffective Pedro. The icing on the cake was his third, and most baffling, substitution of Davide Zappacosta for Cesar Azpilicueta.

But Chelsea actually had their chances to take the lead in the first half. David Luiz’s dipping and swerving free kick forced Sergio Romero into an awkward parry away from goal. The rebound fell kindly to Pedro who volleyed straight at Romero.

Jorginho showed a glimpse of the player he was at Napoli when he found Gonzalo Higuain with a ball over the top of United’s defence. Higuain expertly plucked the ball out of the air, but couldn’t find space inside the near post with the angle narrowing.

Higuain probably should have scored a minute later when Azpilicueta’s cross found him unmarked just inside the United penalty area, only for the Argentine to head wide.

United looked the more confident side in the first half, and just after the half-hour mark, their attacking pressure paid off.

Pogba has looked a different player since Ole Gunnar Solksjaer took over, and his in-swinging cross from the left found Ander Herrera who had mysteriously been left free by Marcos Alonso, and Herrera stopped to head in past a helpless Kepa Arrizabalaga.

Just before the half, Pogba showed he can score goals, too, when Marcus Rashford torched Alonso and whipped in a cross that the Frenchman leapt to power past Arrizabalaga to give them a 2-0 lead.

No changes were made at the half from Sarri, but Chelsea might count feel unlucky that Nemanja Matic stayed on the pitch. Having been booked in the first half for fouling Eden Hazard, Matic two quick fouls on the Belgian but escaped a second booking.

Aside from that, Chelsea looked utterly confused and sort of went through the motions in the second half, much to the chagrin of the crowd who were either fed up enough to leave early or simply use their voices to express their displeasure through various colourful ways.