Beside the tram tracks that run all the way down to Blackpool and the Pleasure Beach, just along from the hulking iron anchor embedded in the pavement at the start of Fisherman’s Walk, they were doing a brisk trade at The Eating Plaice as kick-off edged closer.

One of the ladies behind the counter upbraided a customer who was taking his plate of fish and chips through to the restaurant. ‘You’ve done yourself there, love,’ she said. ‘If you’d ordered in there, you could have had fish and chips, mushy peas, a brew and bread and butter for £10.95.’

There is a frontier feel about this town, a bit like Barrow-in-Furness on the other side of Morecambe Bay. Sea salt in the veins and a harbour that was once home to a flotilla of trawlers. The wind blows through it so hard it whisks away anything that is not nailed down. The Vintage Emporium and Odditorium advertises its wares near the seafront.

It feels like giant-killing country here. Especially on Tuesday evening when a gale blew through the ground, bending the corner flags and threatening to sweep laptops off the press tables and dislodge red and blue hats from the heads of the Cod Army regulars who filed into the stands and leaned against the crush barriers on the terraces behind the goals.

This was Highbury, but not as Arsenal know it. There is nothing Art Deco about any of the stands at Fleetwood Town’s delightful ground. The capacity is 5327. The trendy restaurants of Upper Street are not a short walk away down Holloway Road. This is a different kind of Highbury. A single-storey sports and social club sits behind the touchline opposite the main stand. A banner proclaiming ‘Up the Cods’ hung behind one of the goals.

It is more than 20 years since Arsenal – who brought 1100 fans north with them - played the final game at their Highbury but even though this Carabao Cup fourth round tie on the Fylde Coast only pitted them against a team that languishes two points outside the relegation zone in League Two, 85 places adrift of them in the pyramid, Mikel Arteta picked a strong side.

It is a million miles from the Ballon d’Or ceremony at the London Palladium, where Arteta had lost out to Luis de la Fuente in the manager of the year category, to this football outpost by the sea but the Arsenal boss gave every signal that he and his team were approaching the task with relish. His line-up included Viktor Gyokeres, Kai Havertz and Myles Lewis-Skelly.

They are not strangers to tricky trips like this. They negotiated a visit to Mansfield Town’s Field Mill ground in the FA Cup last season with aplomb. Teenagers Max Dowman and Marli Salmon started that game just as they started this one. Arteta also handed a debut to 18-year-old Ceadach O’Neill.

Arsenal were at Bayern Munich last week and now the champions were playing their part in the biggest game in Fleetwood’s history. The game even began with a rare curiosity – less than two minutes into the match, play was halted by the sight of a drone of unknown provenance hovering over the pitch.

The referee informed both managers of the issue and the players tried to keep warm in the hiatus. The teams were brought to the sidelines before play was resumed after a seven minute delay. The drone operator, apparently, was apprehended by police in a nearby park. Stick the whole episode in that Odditorium.

Midway through the half, there was some football drama, too. Aaron Loupalo-Bi ran on to a through ball and held off Salmon before turning him and rifling the ball through the legs of Ilhan Meslier. Never has Highbury celebrated a goal against Arsenal with such unbridled joy. The theme to Captain Pugwash, the Fleetwood goal music, carried across the ground on the breeze.

Fleetwood defended well and with great commitment but five minutes after the interval, with Martin Odegaard introduced to the fray, Arsenal were level. O’Neill swung a fine cross into the box and after a bit of pinball, Gyokeres forced it over the line. Five minutes later, Jay Lynch pulled off a last-ditch save to deny Havertz from close range.

Odegaard changed the complexion of the game. Arsenal dominated midfield now and started to turn the screw. Havertz prodded into the side-netting, Lewis-Skelly skied an effort over the bar from the edge of the six-yard-box. ‘Champions of England, you’re having a laugh,’ the Cod Army sang.

Five minutes from the end, Dowman, who had been ineffectual, reacted to a challenge by Harrison Neal and kicked him while he was on the floor. Referee Michael Salisbury showed him a straight red card. Dowman is still only 16. As he trudged off the pitch, Arteta muttered something in his ear. The kid was doing his GCSEs last summer. This will be a valuable part of his football education.

Lynch saved brilliantly from Ben White in the dying seconds and the tie went straight to penalties. Arsenal, incredibly, blinked first. Bruno Guimaraes hit their fourth penalty to the keeper’s left and Lynch dived to push it out. Conor Haughey stepped up to take Fleetwood’s fifth and smashed it into the roof of the net.

Fleetwood were in the quarter-finals of the Carabao Cup after causing the greatest upset in the history of the competition. The Cod Army invaded the pitch at the end. Highbury had done its worst. Arsenal were out.