The mud-spattered Mercedes van is parked up pitch-side, its back doors flung open and all the training paraphernalia pouring out on to the grass. Cones, metal-framed dummies, energy drinks, bibs and strapping fall to the turf. The surrounding area is littered with flip-flops and trainers, some snazzy, others scuffed and worn, with the entire squad having laced up their boots al fresco on the touchline. This could be park football on a Sunday morning. It is actually a professional team reborn.

The setting is Langstone student village, mid-morning on a Friday, and on the university campus's main pitch the players of Portsmouth Football Club are preparing for a critical game against Hartlepool. Pompey, FA Cup winners in 2008, a side who confronted Milan in the Uefa Cup the following season and seven years a Premier League club, are five points above the condemned at the foot of League Two, with their third manager of term, Andy Awford, barking orders. "Be physical. Get in their faces. Be horrible. Squeeze the line. Rash him, as tight as you can."

It is Awford's second spell in caretaker charge this season and, backed up by Alan McLoughlin, Paul Hardyman and Martin Hinshelwood, his tenure will extend to the summer at the very least. The players are revived in his company.

This is the modern-day Portsmouth, the top-flight club brought to their knees by financial mismanagement now transformed into a setup proudly owned by their supporters and whose ability to thrive as a Football League member may yet define the perception of community-run clubs. Their story requires some context, though there is no need to linger over what brought them to their lowest ebb before the fans provided salvation.

The main entrance to Fratton Park from Frogmore Lane. Photograph: Sean Ryan for the Guardian

The decline is well-documented. There were two long periods in administration: the first after the Russian-Israeli owner, Sacha Gaydamak, cut off the funding in 2009; the second, in 2012, followed the arrest for alleged bank fraud in Lithuania of a subsequent owner, Vladimir Antonov, who left £35m debts, plus £17m owing to another former owner, the Hong Kong moneylender Balram Chainrai.

Mention of the names will for ever provoke shudders of apprehension down the spines of those associated with this club. There were three relegations in four seasons, the squad stripped bare even if it was liquidation that was the truly sickening fear, before the city bit back. The Pompey Supporters' Trust and their partners, 11 local businessmen "presidents", mounted their bid and, on 10 April last year, Chainrai finally agreed to release his charge over the stadium, Fratton Park, and settle for a price of £3m.

Saturday marks the first anniversary of the takeover's completion, the trust having raised £2.3m with the presidents investing £1.7m. This is the country' biggest community-owned club, backed by 10,600 season-ticket holders, 3,500 trust members, and a vociferous support. They are a club with a chance to heal and grow organically.

A once-bankrupt institution is fast becoming a financial success story, no longer reliant upon sugar-daddy funding – with the coffers in their healthiest state for 40 years. Ticket sales, corporate hospitality and renewed commercial activities, allied to cost savings, have led them to outperform their original budgeted forecasts. This club committed to pay in excess of £8m still owed to 21 former players by July 2016, though those debts are being cleared quicker than expected. "For the first two years we were going to have to pay more to players who don't play for us than the ones that do," says Ashley Brown, chairman of the Pompey Supporters' Trust and one of the body's three members elected to the board. "Welcome to the crazy world of football.

John Portsmouth Football Club Westwood. Photograph: Sean Ryan for the Guardian

"We had a loan of £1.45m from the city council, which we paid off in two months, and a loan of £1.2m from our property-development partner, Stuart Robinson, which we agreed to pay off within a year and that's on schedule. We're ahead of schedule on the football creditor debts. The final parachute payment, which runs out this summer, has helped us to do that, but what has been achieved has been quite amazing considering where we started: no players; no management structure; no kit sponsor; no shop; we had to rip up all the hospitality and bring it in-house. The transformation has been astonishing."

It had felt almost like starting from scratch but the talk now is of £1m in summer developments at Fratton Park – new drainage, a relaid playing surface, better facilities for disabled supporters – and an £800,000 investment in a new training ground at Roko, Hilsea, which will mean the days spent changing on the sidelines at Langstone will soon be over.

"We've been in discussions for five or six months, some quite sensitive because, as a community club, we clearly can't displace another community club," says Mark Catlin, their Barking-born chief executive who arrived via Bury. "But everything's been verbally agreed, we're at the solicitors stage now. Having that base for the team and the academy will give us some of the stability the football side of the business has needed."

The hope is the diggers will move in next month, with the facility – designated changing rooms, initially two pitches and a Championship-quality gym area – to be ready by September. The club's high‑net‑worth fans are funding a large proportion of the development, with other monies to be raised through schemes over the weeks ahead. "This has been an eye-opener for all of us, but we are committed to making it work," adds Catlin. "The real pressure is the fact all these people have scrimped and scraped and put their hard-earned cash into the club to keep it going, and that is one hell of a responsibility to take on."

The city has been galvanised by the reclaiming of its club, the Pompey brand no longer toxic and, instead, restored as a source of local pride. Those overseeing Pompey in the Community, the charity arm of the club, are best placed to confirm as much. "There's a different feeling now," says Clare Martin, the body's chief executive. "People feel as if they belong to something. We were delivering at a lot of schools, even during the two administrations, but we're now picking up new schools all the time. Pompey is the city as well as the club, and people want to be associated with Portsmouth again."

The 46 projects run by the community scheme touch about 37,000 individuals, aged from three and 93, the Pompey brand engaging all-comers, whether it be on educational projects, health and inclusion initiatives or football coaching courses. The club's study centre is a constant hubbub of activity, the projects benefiting from player appearances or free tickets, and all offered under the Pompey umbrella.

Inside the stadium, celebrating bygone days. Photograph: Sean Ryan for the Guardian

"Our 'extra time' project for the over-60s was supposed to run for five weeks but two of the old boys burst into tears when we said it was the last session so we extended it to 13 weeks," says Martin. "We've also run a 10-week 'back to work' programme and, at the end of the course, 62% of the participants found full-time employment. Whenever one of them got a job, we all felt as if we got the job."

In a city where a study conducted last year by the Campaign to End Child Poverty suggested 27% of children are living in poverty, such initiatives are invaluable. "Portsmouth has some of the most deprived areas in the country, it's a tough city, so a lot of the work is centred on literacy, numeracy, core skills the kids don't necessarily get otherwise," says Brown. "We talk about being a community club but if this branch of the organisation didn't exist, we wouldn't deliver anywhere near as much as we ought to.

"People had become disassociated with the club, there was disillusion, so the last year has had a cleansing effect. A lot has been achieved. But, to be honest, there has been so much concern recently about the league form we haven't had a chance to look back at the last year with any great sense of pride. We've been focused solely on the league table. When we have enough points and everyone breathes a sigh of relief, we'll have a quick reflection on what we've done and think about how we can do things better. We're not having this again."

Players leave their street shoes on the sideline while they train. Photograph: Sean Ryan for the Guardian

Full-time is approaching against Hartlepool and the strain is starting to show. Awford, suited and booted, is pacing his technical area, cursing his team's slackness in possession and bellowing instructions to anyone who will listen. Above him in the south stand the chairman, Iain McInnes, feels as if he has been kicking every ball, thumping the front of the directors' box in frustration and forever leaping to his feet to join in with the clapped encouragement emanating from the Fratton end. Noel Blake and Vince Hilaire, former players of pedigree, are fidgeting due to the tension.

Catlin, further down the front row, has been consumed with nerves since well before kick-off, his jitters hardly eased pre‑match when news filtered through that the Tannoy announcer had broken down at traffic lights on the A27 at Farlington en route to the game. A few frantic phone-calls to a local pick-up firm later and he was delivered. "That's a community club in action," offers one trust member.

Memorial wall inside the stadium. Photograph: Sean Ryan for the Guardian

Pompey score in the second minute, miss a penalty in the fifth, and endure six minutes more of added time with their lead still fragile. "This is just the way we do things," McInnes says once the whistle has shrilled. "Nothing's ever simple when it comes to Pompey."

Where progress has been marked off the pitch over the past year, it has continued to be traumatic on it, a campaign best summed up in numbers: four contracted players at the start of last summer; two permanent managers since; two assistants, four goalkeeping coaches and two physios; 46 players used; 51 points accrued. Guy Whittingham, the manager who began the season, was a club stalwart and his exit in November was painful. Richie Barker came highly regarded, along with Steve Coppell – employed in an advisory role and only claiming expenses – but lasted only 109 days. Barker's tenure encompassed 20 games, four wins and 11 goals, with the team failing to score in six home fixtures.

In the context of four years of blood-letting, that the framework was weak was perhaps inevitable. "I always imagined our biggest challenge would be off the pitch, but it's been on it where we've been really tested," Catlin says. "Every time we thought we were up and running we've been kicked in the teeth again."

League Two is unforgiving. The bookmakers had installed Portsmouth as pre-season favourites for promotion, hoodwinked by the optimism generated by the takeover. The immediate target is very much survival.

"It goes back well beyond the summer," says Awford, whose association with the club stretches to 25 years as player, coach, head of academy and now caretaker manager. "Two administrations in three years scarred us, and the rebuild is a bigger job than people thought. It will heal, but it can't be a quick fix because there was so much wrong. Even I lost track of who actually owned the club at one point. Crazy times … The FA Cup, Milan, I wouldn't give it up for the world, but ultimately it was to the detriment of the club."

Images from that most superficially glittering period in Portsmouth's recent history, of Peter Crouch and Sol Campbell, or Kanu and Jermain Defoe, wearing blue and white, still adorn the corridors at Fratton Park. Yet once they were demoted from the elite, all semblance of stability on the pitch evaporated. The Austrian midfielder Johnny Ertl, once of Crystal Palace and Sheffield United, feels like a veteran of this squad. He initially signed in the autumn of 2012 on a succession of short-term deals – "nine or 10 of them" – before finally earning a three-year contract last summer. "I've trained with 80-odd players in my two years here, and we must have signed 15 last summer alone, players we had to try and integrate at four different training venues at the start of the season. The club is like a big tree which blossomed in the Premier League, giving night fruits with the FA Cup, and then they chopped it down. But the fruits were rotten. Now, as a League Two club, we need to lay down new roots so we can grow again.

Goalscorer Adam Webster celebrates with Jed Wallace. Photograph: Sean Ryan for the Guardian

"We don't have the resources of the past. We are a community club, we don't have a chairman who will pump money in and buy instant success, but everyone is trying his best to rebuild, laying the foundations with the academy, the training centre. That's why I stayed here. I love the people, the club, the fan base. But we knew it would start in a difficult way." Ertl has just completed a masters in business administration, affiliated to Wels University back home and supported by the Professional Footballers' Association, examining the financial situation in British football. He envisages a future as a director of football. He may be needed.

The 31-year-old was cast aside by Barker but returned to the lineup, as captain, in the victory against Newport in Awford's first game back. His steel and commitment helped curtail a six-game winless run. Against Hartlepool the caretaker manager restored Simon Ferry after a 14-game absence, his young side bustling with vitality from the outset. Jack Whatmough, an England Under-18s defender who has just signed a three-year contract, excelled at centre-half to the coos of the 11 scouts sitting in the south stand, while Nicky Shorey, an England left-back under Steve McClaren, scuttled up the flank.

A crowd of 15,273 bellowed their encouragement and defiance – "We own our own club", "We will never die" – as McInnes went through his agonies in the directors' box and Hartlepool mustered a flurry of stoppage-time corners. The relief was palpable at the final whistle, even if the visitors' threat had been fitful. It was the first time in more than a year that Pompey had secured successive league wins.

The result left them five points clear of the cut-off, their timely surge of momentum maintained at Dagenham & Redbridge last Saturday, when a side with faint play-off aspirations were dismantled and defeated 4-1. Northampton's own flurry of recent results has seen the gap from the bottom two shrink to four points, though other clubs have been leapfrogged and the contests with Bristol Rovers on Saturday and at Sixfields against the Cobblers on Monday will surely prove decisive. A fourth relegation in five years is unthinkable but, while it would be a huge blow to the community club's pride, it would not threaten them as a going concern. That, in itself, speaks volumes.

"But we won't go down," Awford adds. "Although there's a long-term target to put the club back into the Championship, that process would be set back unless we sort out the here and now, and that's what we'll do. I'm all about longevity, but my immediate task is short-term. Four games, two weeks, stay up." Then the rebuild kicks on.