Arsene Wenger’s team selection yesterday evening, with several senior players rested in advance of the Europa League semi-final next Thursday, let everyone know that he was resigned to defeat on his final visit to Old Trafford.

And yet, you wondered if Arsenal’s young players could be much worse than the senior ones who have failed so many times in recent years. In the event, they were giving a decent account of themselves until United scored following a mistake by one of the most experienced players in the Arsenal team, Granit Xhaka.

The mistake is worth considering because it revealed a lot about what is missing at Arsenal. Paul Pogba was coming through the middle with the ball, weighing up his options, when Xhaka made his mind up for him by flinging himself across Pogba’s path, and out of the game.

Pogba, who had not even had to fake a shot to tempt Xhaka into sliding out of his way, played it to Romelu Lukaku and then ran into the box to score.

Every player makes mistakes in every game, but Xhaka’s mistake was so basic that it made you wonder what can be happening in Arsenal training. How can a professional player sell himself so cheaply in such a situation?

Teams that are good at winning the ball back don’t get that way by accident: you have to know what you are doing, and you have to work at it. Look at Jürgen Klopp’s pressing system at Liverpool. There is more to it than simply hyping up the players and telling them to get after the opposition.

For players in a Klopp team, there are two basic rules you have to follow when you’re pressing an opponent: you stay on your feet, and you don’t commit a foul. If you break either of these rules you will be hearing all about it from Klopp.

Defensive lapses

What Xhaka did showed us that things are different at Arsenal. You can do these sorts of things and stay in the side. This is why Arsenal, for a long time now, have been prone to the sort of basic defensive lapses that should not happen at a top club.

Think back to January, when they lost 4-2 to Nottingham Forest in the FA Cup third round – the first time they’d been knocked out of the competition at that stage under Wenger.

At 0-0, Forest won a free-kick on the right and Arsenal set up a two-man wall on the edge of the box, just a yard or two from the goal line. But the Arsenal defenders in the centre stood along the six-yard line, apparently oblivious to the fact that the position of the wall meant that any opposition player could stand goalside of them and still be onside.

None of the Arsenal defenders noticed, but Erik Lichaj and Forest’s setpiece taker Kieran Dowell both did, and a moment later an unmarked Lichaj had headed Dowell’s driven free-kick into the net from barely a yard out.

The Europa League is Wenger’s last chance to leave Arsenal on a high, and the semi-final against Atlético Madrid is fascinating because Atlético are the anti-Arsenal. This is a team that doesn’t just know how to defend, but actively loves defending.

Their coach, Diego Simeone, summed up their attitude in the wonderful tribute he paid his players after the 1-1 draw in the first leg: “The team had to keep going every minute. That’s the most beautiful thing about football . . . You guys have no idea how difficult it is to defend. Football is about playing and playing is the fun part, but you’ve got to have balls to defend with 10 men for 80 minutes.”

Confident vibe

Wenger believes his team plays best when everyone is having fun, and he has always tried to encourage a vibe of confidence and creativity, to the point where it appears as though he avoids working on defence because he doesn’t want to cloud the players’ minds with negative energy.

Simeone turns negative energy to his advantage. Xavi Hernández has marvelled at how Simeone can get a talented player like Koke to submit himself so completely to the demands of Atlético’s defensive system, to chase and scrap like a man with one-tenth of his ability. It’s because Simeone knows how a team can be bound together through mutual sacrifice; the team that bleeds together, stays together.

He understands that, in a strange way, players are happiest when they are suffering. The deep satisfaction Atlético’s players had at the final whistle last Thursday is a feeling that Arsenal’s players have had too seldom in recent years.

Some media speculated that Thursday’s first leg amounted to Simeone’s audition for the Arsenal job. It’s true that Simeone’s idea of what football is all about is in tune with the ancient, half-remembered rhythms of Arsenal in the pre-Wenger age.

But the idea of Simeone replacing Wenger directly is ridiculous. The culture shock would be too intense, for Simeone as much as for the Arsenal players.

It’s enough for Arsenal to learn from the example of Simeone and his team. As they seek Wenger’s replacement, they should not be looking for a “statesman”, or a “healer”, or someone who is good in press conferences, or someone who has a reputation for playing “progressive” football.

They should be looking above all for someone who understands the power of struggle and sacrifice, someone who will push the Arsenal players to their limits, because deep down, that’s the kind of coach most players really want.