JUST when Arsenal fans thought they’d seen it all, they had to watch the first half of the Europa League Round of 32 second leg debacle at home to Ostersunds FK.

The Gunners were a shambles: uninterested, and outplayed by the Swedish minnows, who sparked boos from the home faithful by winning 2-1 at the Emirates in a game the hosts were accused of being too arrogant to take seriously.

A 3-0 win away from home was enough to secure progress, but clearly an eye – or both – were on Sunday night’s Carabao Cup final against Manchester City.

Half-time was a saviour for the Gunners to recalibrate, given the players look shell shocked, fans were incensed, and ugly body language ensued on the park against a side coached by Englishman Graham Potters, who has steered them to a first European campaign after a rise from the fourth tier since 2010.

With tiny Ostersunds enjoying the lackadaisical approach of the hosts – wearing blue, not the traditional garb – a serious calamity was ensuing until Saed Kolasinac’s relieving goal at the start of the second period.

True, Wenger rung the changes, but even he admitted complacency seeped in as the back four wobbled, the midfield disappeared and the attacking unit was largely toothless. Indeed, Ainsley Maitland-Niles was hooked at half-time for Granit Xhaka, Calum Chambers was culpable, probably for both goals, while Danny Welbeck was rusty.

“We were not at the races in the first half,” said Wenger.

“In the first half we were in trouble and in danger because we were complacent, not focused and were open every time we lost the ball. We had no ideas with the ball and that’s why we were in trouble.

“We responded very well because we did the job to qualify, but that’s what we have to take from the night and that’s all.”

He added: “We prepared properly and in a serious way.

“But you have external circumstances such as the fact we won 3-0, the fact that we have another big game on Sunday, the fact that people subconsciously think you just have to turn up to win the game. Football doesn’t work like that.

“It’s better not to talk too much tonight, and focus on our next game.”

Speaking on BT Sport, Martin Keown, one of Arsene Wenger’s former charges, erupted: “Kolasinac doesn’t seem the same player as the one who joined – he was an animal but he doesn’t seem hungry now.

“The goal was coming, not one part of the Arsenal team is functioning, the team is imploding.

“I am embarrassed watching as a former player never mind how Arsene Wenger must feel. It’s a big week for Arsenal, they’re not going to win the Europa League with a performance like this.”

Republic of Ireland assistant manager Roy Keane said on ITV: “Arsenal are a great example of how not to start a game of football.

“They are so slow out of the blocks. Poor attitude, no energy, no desire. It’s not like a light switch, you can’t just turn it on and off.

“A lot of that will come from the manager and his coaching staff, but ultimately it has to come from the player. You have to motivate yourself. You have your pride and you want to do well for yourself, your team-mates, your family and to turn up like that was a shambles.

“We have seen it so many times from Arsenal. They went to Nottingham Forest (in the FA Cup last month) with exactly the same attitude and lost. You make excuses for Arsenal all the time, but it’s a load of rubbish. The Arsenal players must drive you crazy. A shambles.

“You look for your senior players to lead by example…when Wilshere (below) is your captain, to me, he is probably the most over-rated player on the planet.”

Some of the commentary has been truly savage.

The Telegraph’s Jeremy Wilson declared it, “among the worst results in Arsenal’s entire history”.

“Humiliation was narrowly averted but, as an audition for Sunday’s League Cup final against Manchester City, Arsenal’s fringe players delivered the footballing equivalent of forgetting all their lines and then falling off the stage in a big heap,” he wrote.

The Mirror’s Darren Lewis smashed the arrogance that undoes Arsenal against supposedly inferior opponents, declaring the performance “embarrassing, abysmal and the latest chapter in the Arsenal hall of shame”.

“Too many big-time Charlies. Look at the teams that have stuffed them in the Premier League - Stoke, Watford, Bournemouth and Swansea,” he wrote.

Look at the team that put them out of the FA Cup - Nottingham Forest. Against the lesser lights they appear not to want to put in a shift.”

The Guardian’s David Hytner added: “Arsenal had made the gesture to change their colours because Östersund have only a red kit and a white one. The hosts proved even more obliging in the first half. The concessions were the product of abysmal defending, with Calum Chambers particularly culpable, but they had been signposted.”

Robert Pires has encouraged his former boss to push to emulate Manchester United last season and win the Europa League.

“Arsene Wenger is always under a lot of pressure, especially from the fans,” said Pires. “When you start the season the first objective is to win something at the end of the season.

“He has two great opportunities. On Sunday, to win the Carabao Cup, and the second - why not to win the Europa League? He will be very focussed and cope with the pressure.

“It is not a problem for him.”

It will be, if they play like they did in the first-half again.