It is half-time and one of the Leicester City players runs straight down the tunnel. “F------ bull!” he shouts, followed by a team-mate who warns: “They are going to whack us.”

It is the first round of the FA Cup and Leicester, winners of the trophy just five years ago and Premier League champions five years before that, are staring at the humiliation of a potential exit.

Oxford City, in the sixth tier of English football, playing in National League North and 64 places below Leicester in the pyramid, are threatening one of the greatest upsets in the competition’s rich 154-year history. And what would be the biggest-ever result since the club’s formation, just 12 years after the Cup was first played.

It is 1-1. Predictably, Leicester have had 72 per cent possession, but have had just two shots on target. City have had four. And looked the more dangerous. Especially from set-pieces.

Leicester are raging at City’s equalising goal, direct from a corner and scored – in of those bitter ironies – by Leicester fan and midfielder Scott Pollock, who had unsuccessful trials at the club as a goalkeeper. Except Leicester are convinced their goalkeeper now, Franco Ravizzoli, was fouled as he lost his footing on the slippery 3G pitch with Pollock’s delivery looping over him and high into the net.

Were there added factors in the mistake? The day before the game, after all his preparation and analysis was done, City manager Ross Jenkins had put it bluntly as he stood in his office.

“Under our own floodlights, which are not the best, and with the leaves on the pitch, we’ll see if they can play,” the former Watford midfielder warned.

There was even an instruction not to sweep that foliage away before kick-off while the wattage of those lights was dim in the Oxford gloom. Welcome to the National League. Welcome to a different form of marginal gains.

The Leicester protests continue as the players re-emerge for the second half with referee Andrew Humphries the target. “It’s a clear foul,” he is told, over and over, while the message heard from the City dressing room is also clear: “Keep doing it.”

The pressure is certainly on Leicester and their manager, Russell Martin. Losing this tie would represent a new low as the club fights to arrest its dramatic descent. It is simply not something they can face. Something they cannot contemplate.

“Listen, we have been put on Friday night on TV for one reason – it’s because everyone wants to see an upset, and that’s what the FA Cup is about,” Martin says, with the game televised by TNT Sports. And he has gone strong. He can take no chances. Stronger than he normally does in knockout competitions, with City’s young team of analysts having worked out that, in his managerial career from MK Dons, Swansea City to Southampton, Rangers and to Leicester, Martin has averaged more than seven changes for cup games.

But this time only players such as Harry Souttar, Will Smallbone, Will Alves and Conor Chaplin, for whom the plastic pitch might have been unforgiving with their injury histories, have been left out. Martin is acutely aware of the stakes and what defeat would mean and had trained on a similar artificial surface the day before.

Despite their fall to 10th in League One, Leicester’s budget, hugely cut over the summer after relegation from the Championship, still stands at £30m. A mind-boggling difference to City’s players averaging just £700 a week. Some younger ones are on as little as £300.

“There’s a lot of flexible kind of working, and there’s only so many hours you’re at a football club,” reasons City’s chief executive, Justin Merritt, of how his players supplement their income.

“For example, Scott Pollock is a bit of an influencer on social media. He was the original winner of Hashtag United’s ‘find the next player’ kind of thing.”

Pollock, 25, also runs a bagel company. His goal will certainly have been good for business on every front with Hashtag United, originally a social media phenomenon, posting on X: “Remember the name”. As they did when he won their competition.

“For a lot of our lads, some of them feel that they should have had the opportunity,” Merritt adds. “If you look at every single one it’s kind of they’ve all got their own story, as many players at this level have.”

‘We get at them’

It is 10am, the day before the Cup tie. City players have squeezed into a small meeting room at the club’s MGroup Stadium, known locally as Court Place Farm, which is a hive of activity after the decision was made, late on, to erect a temporary stand in front of the main bar and fill in the corners of this tight little ground just off the Oxford ring road. It brings the capacity up to 3,500 – which is quickly sold out. There are cables, tools and workmen everywhere as Jenkins begins his presentation.

The room is so small, with blacked out windows, that his coaching staff – including former West Brom and Watford defender Paul Robinson – have to congregate in the doorway as Jenkins, an intense 35-year-old, talks.

“They have about 40 players and can play a back-three or a back-four,” he says, laying out how difficult it will be to predict Martin’s approach – even if the way Leicester play will be more predictable. “It’s irrelevant who they play,” Jenkins says. “We need to show the shape.

“For me, the back three can be exposed. They build up really slowly. They are not a back three who overlap, like the old Sheffield United.

“They have some errors in them as well… so forcing errors, being brave in the press, locking on, really squeezing and condensing the pitch and get your rewards.

“We have to be brave. There has to be a time when we get at them.

“Souttar is a big ‘un but cannot move.”

In the event the 28-year-old Australian international does not play.

But there is a more prophetic statement from Jenkins. “If he plays, [Louis] Page is a really tidy player,” he says, with the 18-year-old midfielder starting the next day and opening the scoring, after a lovely flowing move, with a left-foot shot, 25 yards out, which flew high beyond City goalkeeper Jonny Maxted. It is Page’s first goal in professional football and, certainly, a memorable one. “How s--- must you be, we’re winning away,” sang the Leicester fans, with 560 of them inside the stadium. Such is Page’s pedigree that Leicester turned down a £15m bid from Manchester United for him in the summer.

“They are very young. They have legs and energy but they might lack experience coming to a place like ours,” Jenkins finishes, by way of encouragement. But there is a warning. “He [Martin] has had a lot of bad press over the years. But his teams can play,” Jenkins says. And with that the presentation – 11 minutes in all, to keep it brief – is over as the players file out for their final training session before what, for some, will be the biggest game in their careers.

Fraudsters, Bobby Moore ... and a five-year plan

City are ambitious. “The Hoops” have a five-year plan to get themselves into League Two having, 36 years ago, fallen so low that they were playing their games in a nearby public common, Cutteslowe Park. Their history also includes a remarkable spell when they attracted Bobby Moore as their manager – with Harry Redknapp as his assistant – with a Daimler car added to sweeten the deal. An American owner was later imprisoned for fraud but now they are on a much firmer footing, owned by Carl Dunton, an Oxford University graduate and lawyer who was based in Singapore and runs an investment company called Spark Strategic Partners. Dutton flew back from Japan for the tie.

“This is the biggest game in our modern history,” says Merritt, a former midfielder himself, who was with Watford from the age of nine to 19 and was in the same England under-age group as Sir David Beckham. He has held a number of roles at the club, including playing and managing them.

“We’re almost like running a leisure centre as well as a football club. The facilities here are open eight o’clock in the morning till 10 at night, nearly every day of the week.

“So even on the eve of what essentially is the biggest game the club’s faced in modern history there’s a year-six girls’ tournament here.”

How game-changing will this Cup tie be? Merritt is coy, as he is about City’s budget. But the conservative estimate is around £100,000 with extra bars and terracing also being added. “This is not going to be a golden ticket,” he says. “But it puts us on the map.”

Most of City’s players have had shots at the big time, not least their veteran forward, 36-year-old former Watford and Udinese striker Fernando Forestieri, who has played against Lionel Messi and Cristiano Ronaldo. The Argentinian starts on the bench.

“The other thing for Leicester is if they do take us too lightly, they might be surprised how good the level is as well,” Merritt says. “There is absolutely zero pressure because no one is in their right mind is expecting that. There’s always hope.”

Back to reality: Darlington away

It is 10pm and Adele’s Somebody Like You is blasting out from the home dressing room. The final whistle has gone. The tie is over. The same song had been played almost four hours earlier as the City players arrived, ahead of the game. “Is this the music for an FA Cup upset!” had shouted defender Canice Carroll as he walked through the doors.

In the end there is no upset. Leicester have deservedly won 4-2. But not without a fight. City acquitted themselves brilliantly. It is not until Leicester score their fourth goal, as late as the 82nd minute through substitute Tommy Watson, that the tie is finally put to bed and the shock dies.

In the event, Leicester did start as City predicted with a back three but after that uncomfortable first-half, Martin changed shape – as was again predicted – and it is the introduction of the prodigiously talented Harry Howell, the 18-year-old winger on loan from Brighton & Hove Albion, that transforms the tie. The teenager is rightly later named as man of the match.

Even so, City can take pride in how much they rattled a Leicester team who included Bobby De Cordova-Reid, Luke Thomas and John Lundstram, all former Premier League players, as well as a cadre of young talents and Danish striker Emil Riis who was signed in the summer from Bristol City.

It is Riis who restores Leicester’s lead, with a header after 53 minutes after City had dominated the early stages of the second half, buoyed by being level. When an early shot from Kamari Doyle catches out Maxted six minutes later it appears to be game over. “It does flatten you,” Jenkins later says.

But, to City’s huge credit, they struck back with a fine finish from captain Josh Ashby as he ran through to lift the ball over Ravizzoli and fuel hope that extra-time, even penalties, could be reached. “Look what it means!” declared TNT Sports commentator Sam Matterface, perched precariously on the low main stand accompanied by co-comms and Oxford local Martin Keown. And the scenes reflected that before Watson sealed the result.

The relief, rather than the disappointment, for City was palpable. The reality was they feared the worst and their own humiliation with Leicester running up a damaging score. Instead, they can take heart. Their goal is promotion back into the National League.

“Back to reality Tuesday. Darlington away,” says first-team coach Jordan Piper as he mingles in the bar afterwards with Pollock who is clutching an unopened bottle of champagne after being City’s best player. In fairness, Piper’s preparation has already started. In his hand is a yoghurt pot, rather than a pint of beer.