A beautiful story is unfolding on the south coast of England. Fifty years after their team of second tier underdogs pulled off one of the biggest shocks in FA Cup history by beating Manchester United in the final, Southampton are threatening to do it again.

Their new incarnation of second tier underdogs are following match-winner Bobby Stokes and his teammates of 1976 into folklore by making it back to Wembley for the semi-finals half a century later.

This time, their top tier victims were an Arsenal team whose season is shrinking. Until a fortnight ago, they were in pursuit of the Quadruple but they were humbled by City in the Carabao Cup a fortnight ago and last night they fell victim to one of the biggest giant-killings of the season in the competition’s quarter-finals.

Their capitulation, albeit with what amounted to a second team, will ask yet more questions about whether they can withstand the challenge of City in the Premier League. A few hours before Arsenal’s defeat, City had produced one of the performances of the season to thrash Liverpool at The Etihad and move into the semi-finals.

Now Arsenal will travel to play Sporting in Lisbon on Tuesday night in the first leg of their Champions League quarter-final with uncertainty in their hearts. They dare not falter there because next Saturday, they face Bournemouth at The Emirates, a game they must win if they are to try to halt City’s momentum.

Southampton wore yellow kits in honour of those heroes and they summoned every ounce of emotion they could as they heaped more woe on an Arsenal side who are looking nervously over their shoulders at a City team that looks back to its best and is on the charge again as it eyes Arsenal’s nine-point lead in the Premier League.

Southampton wore yellow kits in honour of their 1976 FA Cup-winning heroes and they summoned every ounce of emotion they could as they heaped more woe on Arsenal

Arsenal’s capitulation, albeit with what amounted to a second team, will ask yet more questions about whether they can withstand the challenge of City in the Premier League

Before the game, Southampton brought the legendary football hard-man of old, Mark Dennis, on to the pitch for an interview. Dennis was nicknamed Psycho before Stuart Pearce was called Psycho so you can guess the tenure of his address.

‘It’s a free hit for us tonight,’ said Dennis, who was sent off 12 times in his career. ‘All the pressure is on Arsenal. Let’s get into them. Let’s win our personal battles in this magnificent shrine of a stadium.’

This a featureless bowl of a stadium when it is empty but Southampton’s fans turned into it into a seething cauldron last night and Arsenal had no answer to the atmosphere or to their opposition.

Southampton had not lost for 14 games going into this match and they deserved their victory. If the match was a triumph for their manager Tonda Eckert, it was another miserable night for Ben White.

The Arsenal full-back was booed in his two appearances for England recently and last night, he was at fault for Southampton’s first goal. Arsenal equalised but fell to a late winner from Shea Charles.

Arsenal suffered an early alarm when Southampton cult hero Leo Scienza ran at the visitors’ defence, broke into the area and jinked inside Gabriel. Gabriel wafted a trailing leg in his direction and Scienza tumbled to the floor. St Mary’s howled for a penalty. Referee Sam Barrott waved play on.

Arsenal soon hit back. They worked a short corner to Ben White, who played a square ball to Gabriel Martinelli. Martinelli curled it towards the top corner and thought he had scored but Taylor Harwood-Bellis threw himself in front of it and headed it over the bar.

Scienza was given a golden opportunity to put Southampton ahead in the 17th minute when Gabriel leapt to try to head clear a long clearance out the home defence and inadvertently flicked it on to the Saints winger.

Scienza was clean through but even though he took the ball around Arrizabalaga, Cristhian Mosquera had got back and was able to take the ball off his foot just as he was about to slide it into the empty net.

If the match was a triumph for Southampton manager Tonda Eckert, it was another miserable night for Ben White

Arsenal have enough injuries without having to worry about another but there was concern when Gabriel appeared to go down with a knee problem and had to be substituted

Arsenal knew they had had a lucky escape but midway through the half, it was their turn to hand Southampton a reprieve. When Martinelli pulled a ball back from the goalline, he found Odegaard unmarked 12 yards out. Odegaard swung his left foot at it but miskicked it horribly and it flew harmlessly wide.

By now, Dowman was growing in influence. He had been bright right from the start but he was beginning to taunt the Saints defenders, turning them one way and then another and bringing a series of decent saves out of Daniel Peretz.

It was an open game, nothing like the heavily controlled, tactially disciplined contests that have become Arsenal’s hallmark in the Premier League. They were particularly vulnerable in transition and when Southampton counter-attacked nine minutes before half-time, they had time and space to shape their move.

Scienza brought the ball to half-way and then left it to Bree to carry it forward. Bree was allowed to run and run but when he floated a cross to the back post, it seemed it would be headed clear easily by Ben White.

But White mistimed his jump horribly and it sailed over his head. Ross Stewart took it down on his chest, let the ball bounce and then smashed it across Kepa with his right foot and into the corner of the goal.

In the second half, Southampton grew even stronger. The game was more about them pressing for a second goal rather than Arsenal trying to force an equaliser. An hour had gone when Mosquera’s square ball was cut out near the halfway line and Tom Fellows drilled his shot just too high.

Arsenal made a trio of substitutions but they made no immediate impact. In fact, Southampton nearly scored again. Scienza cut inside his man on the left and curled a shot over Kepa that clipped the top of the crossbar.

So it was against the run of play that the league leaders equalised midway through the half. Gabriel pushed forward deep into Southampton territory and played Kai Havertz in behind the defence. Havertz pulled the ball back and Gyokeres, who had been on the pitch for a few minutes, turned it expertly home.

Arsenal have enough injuries without having to worry about another but there was concern when Gabriel appeared to go down with a knee problem and had to be substituted by William Saliba.

Dowman thought he had scored the winner seven minutes from time when he bent a left-foot shot towards the far corner but Peretz flew across his goal to push it wide. A minute later, Martinelli’s shot whistled just wide.

But just when it seemed as if it would be a matter of time until Arsenal got the winner, just when it seemed as if Southampton were starting to think their only chance would be penalties, they grabbed the winner.