Lisandro Martínez played here as if lobotomised, launching himself into the game’s fateful challenge with such heedlessness it looked as though he had mentally checked out. Manchester United, if they have any sense, will complete that process for him in January, offloading a man whose disruptive influence is matched only by his self-absorption.

The actions that brought his red card during the 2-0 defeat offered a perfect miniature study in the problems engulfing this benighted club. One moment he was clumsily bringing down Morgan Rogers, infuriated by Chelsea’s record signing using him as a human pitch mop. The next, he was flying forearm-first at Wesley Fofana, not even looking at a ball that the Frenchman was never in a position to win. “Why?” you wanted to scream. Except this is a team where any semblance of rational thinking left long ago.

No wonder Michael Carrick could not even bear to catch the Argentine’s eye as he trudged off the pitch. He had offered forgiveness to Martínez where many other managers would have shown him the door, restoring him to the heart of United’s defence despite the centre-half’s blistering denunciation of the club’s hierarchy for failing to buy enough players during the summer. “I expect more from our technical director,” Martínez said, acidly, after defeat at Atlético Madrid earlier in October. But with three more losses consigning United to a relegation scrap, the club have every right to expect more from him.

All indications are that their search will be in vain. Martínez is a plastic provocateur, whose boldness in front of a microphone contrasts sharply with his enfeebled displays on the pitch. As a senior player, he should have been galvanising his side to respond with snarl and defiance. Instead he provided all the resistance of a sheet of sugar paper, allowing Rogers to saunter through the back four for Chelsea’s opening goal almost in a straight line. From there he lost composure altogether, with his peevish tackle on Rogers for a first yellow card turning out to be a mere foretaste of his foolishness.

Only Martínez could begin to explain his rush of blood, designed purely to deny Fofana the chance of an unlikely header. But his leap was rash in the extreme, with his arm raised and his mind seemingly in meltdown. Referee Peter Bankes needed just a cursory glance at the monitor to confirm Martínez’s dismissal and award the penalty that put Chelsea out of sight. Livid at the decision, he thought about squaring up to Bankes, only for his team-mates to usher him away and condemn him to a walk of shame past Carrick.

For all that this United team have profound technical limitations, they are defective in character as much as anything, with Martínez Exhibit A. If you are going to rock the boat so dramatically in public, pinning the blame on Jason Wilcox for a dismal transfer window, it falls on you at least to attempt to put it back on an even keel. Unfortunately, the defender is simply a malcontent, smouldering with grievances but showing scant appetite to find any solutions. At the very point that United are crying out for a stabilising influence, he produces only a wretched fit of pique.

This brain fade, with his two cards coming a mere three and a half minutes apart, cannot be studied in isolation. Martínez’s body of work at United is lamentable for a player who has been in the squad for two World Cup finals, yielding a pitiful 72 league appearances across four and a half years. He has missed an extraordinary 609 days through injury during his time at the club, and although that is not entirely his fault, it is a reflection of his warped psychology that he has given such chaotic performances when fit. To think, Erik ten Hag somehow convinced United in 2022 that Martínez, a favourite of his at Ajax, was worth £48m. They should be prepared to make a loss on that this winter, just for the satisfaction of removing such a liability from the books.

“The Butcher”: that was the nickname Martínez earned while in Amsterdam, courtesy of the ferocity of his tackling. But at United his carving ability would be inadequate for the Waitrose meat counter. His timing is so loose that he resembles an errant missile, a red card waiting to happen. This was his second this year, after he was dismissed at Leeds in April for tugging Dominic Calvert-Lewin’s hair. Carrick heavily criticised that sanction, but there could be no excuses this time.

Martínez is emblematic of United’s malaise in that he routinely performs far more effectively for his country than for his club. At the past two World Cups, he has lived up to his billing as one of Argentina’s enforcers, even if he hardly endeared himself to England supporters by holding up the infamous “Las Malvinas son Argentinas” (“The Falklands are Argentine”) banner after the semi-final victory. On international duty he is protected, forging a formidable partnership with Cristian Romero. But at United he is so often exposed in defence that his most destructive instincts come to the fore. After letting both his team and his manager down in such crude fashion, he has secured his image less as the butcher than the bungler, a troublemaker whom United would be well advised to cast aside.