Playing Arshavin out wide is a folly Wenger has yet to realise

But Wenger’s explanation for why he took of the precocious youngster did not explain or justify what he did next. He brought on Andrei Arshavin, a decision which provoked a strong reaction not just from the crowd, but from captain Robin van Persie. That van Persie should have mouthed ‘no’ and held his hands up in horror shows all that was wrong with this decision. That was an instinctive reaction from the Dutchman, reflecting genuine disbelief, as well as horror. It was not as though he had a personal issue with the Russian, simply that he could see the impact it would have.

Within minutes, Arshavin, brought on to create a goal, had made the difference. Antonio Valencia, in an advanced but relatively unthreatening position, cut inside Arshavin, and the Russian, rather than turn his body and challenge him, simply admits defeat and allows Valencia to get away from him. The Russian, realising his error, runs back into the penalty area and continues to get in the way of team mates valiantly trying to clear the ball.

The criticism of Wenger afterwards was fully deserved. After all, this was a defeat of his own making. Unusually, this was a game without much controversy. Indeed Mike Dean had a generally excellent game. There was little to bemoan the gods of fortune for. But there was much to castigate Wenger for. It was obvious from the outset that this would be a game won on the wings. Man Utd’s tactics against Arsenal are usually the same – get the ball out wide as quickly as possible, to the likes of Nani and Valencia. Nani continued to torment Johan Djourou, making him look foolish a number of times in the first half until eventually Ryan Giggs also did so, and crossed for Valencia to score.

A Jose Mourinho, Andre Villas Boas or even Alex Ferguson would have taken Djourou off earlier or made another change. To wait until half time was inviting trouble, and it duly came. Wenger took him off at the break and the difference was instant. Arsenal were on the front foot, creating chances, and remained so until Chamberlain came off.

Why he didn’t come off for Yossi Benayoun, only Wenger knows. But though the Frenchman rightly points out that he needs not answer to anyone, he is judged by his actions, and this one was one of his worst decisions. He may have defended himself by saying he’d made 50,000 substitutions in his career, but they can’t all be good changes. And this was certainly among the worst.

Arshavin’s problem is that he seems to lack the stomach and motivation to really be as good as he can be. Undoubtedly talented, he can make a goal out of nothing. When he does leave England, spectators will even look back fondly on a player who produced one of the great individual performances of the Premier League era when scoring four sumptuous goals against Liverpool back in 2009.

But right now, he is a shadow of that player. He doesn’t track back, he seems to lack basic tactical awareness, and continually leaves opponents stranded. A full back playing behind Arshavin finds themselves isolated more often than not.

One of Arshavin’s few good performances this year came against Bolton in the Carling Cup, when he played just behind the striker. This is where Wenger should put him if he is played. That Wenger doesn’t shows tactical naivety on his part. Arshavin can’t defend – so why make him? If you are a winger, you have defensive responsibility. The only positions a player can get away without that responsibility is if they are a centre forward or playing just behind the centre forward.

Arshavin would get away with his laziness if he was as good as Cristiano Ronaldo, whose similar unwillingness to track back at Manchester United was more than made up for by his incredible contribution in attack. But Arshavin is nowhere near as good as Ronaldo, and can’t get away with this on the wing. That Wenger still persists with him in spite of all this evidence is a mystery.