Friday 2 August was opening night for Sheepfolds Stables, a £4m entertainment venue on the north bank of the Wear that replaces the scrapyards and derelict land that used to lie between the Stadium of Light and the river with bars, restaurants and event spaces. People who were there spoke of an enjoyable evening of live music and drinking in the sunshine.

A footbridge is being built to link Sheepfolds and the stadium with Keel Square, which lies a couple of hundred yards upriver of the traditional city centre. There is a conscious effort to refocus Sunderland on the axis running from the 2,000-capacity Empire Theatre and its associated arts spaces through the office development on the site of the old Vaux Brewery to the football venue. After years of stagnation, there is finally a sense of progress.

The mood was of satisfaction, optimism and relief at a regeneration project brought to fruition – it rapidly became despair. Less than half a mile from Sheepfolds, rioters clashed with police in Keel Square. A car was overturned and torched, a police station was set on fire, Filipino nurses on their way to emergency shifts at the Royal hospital were attacked and a mosque was targeted.

Beyond the immediate violence, the awful sense of shock and fear, there are economic repercussions. On Wednesday, the Empire cancelled a performance of The Wizard of Oz while the university shut all campus buildings by 5pm in response to the threat of further violence. The commerce support organisation Sunderland Business Improvement District (BID) spoke of its fear that the riots would deter people from coming into the city with obvious consequences for business. Sunderland is not a city that can readily afford such losses.

On the following morning, as dozens of people gathered in the centre of Sunderland to help with the clearup, it was striking how many were in football shirts. One man, wearing a white 1996-97 away shirt, told the BBC how he felt the riots “misrepresented the city and the club”, which seemed a very telling formulation.

As the clip appeared on the News at One, the phrase seemed vaguely absurd, or at least it must have done to an outsider. Why was he talking about the club and their reputation? Which club? What did that have to do with anti-immigrant riots, beyond the fact that a handful of the rioters were wearing Sunderland shirts?

Yet in another way it made complete sense. How does a city such as Sunderland project itself to the world these days? How many people outside Sunderland ever think of Sunderland in any context other than football (other, perhaps, than its enduring capacity to declare election results early or the Nissan car plant)?

The idea of a football club as representative of a city is commonplace, so familiar now that it perhaps escapes notice how strange or recent a phenomenon that is. Once cities would have expressed pride through their industry, their university or cathedral; now, particularly for post-industrial northern cities, it’s football.

Financially, it’s important, too: tourism in Sunderland was up 3% last year, with away fans visiting the Stadium of Light considered a major factor. When Sunderland fell out of the Premier League, local businesses estimated a 4% decline in trade. Even in the Championship, Sunderland averaged attendances of 41,028 last season; that is a lot of footfall for bars, food outlets and shops.

The relationship has become two-way, as though the city is now as much a projection of the club as the club is of the city. When a city is the setting for appalling events, there is a strange sense in which the reputation of its club is harmed. And at the same time, if people want to show solidarity with their city, if they want to express or feel a sense of togetherness in a time of crisis, what better way to do it than by wearing the club shirt?

The Labour MP for Sunderland Central, Lewis Atkinson, wore a white Umbro away shirt from the late 70s as he helped sweep away debris and spoke of communities coming together to clean up the mess being “the real Sunderland”. But what was equally telling was how the club accept, perhaps even embrace their role.

“When I got dressed that morning,” says Atkinson, “I just knew I wanted to wear that shirt, to me it stemmed from a determination to not allow a minority of thugs to own the most precious identity in Sunderland, to show that it was those of us sweeping away the shards of hate who were the true Sunderland.”

At 11.19pm on the night of the riots, they posted on social media: “Tonight’s shameful scenes do not represent our culture, our history, or our people. Our great city is built on togetherness and acceptance, and Sunderland will for ever be for all. We are stronger as one community. Now. Then. Always.”

It would have been very easy to have said nothing. This, really, has nothing to do with football, even if a handful of the rioters could be seen wearing football shirts. Even if the issue had been raised, the head coach, Régis Le Bris, or some other official could have mumbled platitudes about it being all very sad but best left in the hands of the authorities.

Instead, the club came out within a couple of hours of the trouble with a strong anti-racist message, very obviously taking a side. It may be that was in part informed by the fact the club only narrowly passed the English Football League’s equality, diversity and inclusion standards, but still the message was powerful. Middlesbrough issued a similar statement a few days later as the government called on sports clubs to condemn the riots.

The links between football violence and far-right groups are undeniable, which is why there has been talk of football banning orders for those involved in the riots, and why there has been some off-the-record talk from official bodies that the riots will stop when away days restart. But while anachronistic stereotypes linger, football is far too vast these days to be defined by one outlook. Even in the 1970s, fans of clubs such as Leeds and Tottenham rallied successfully against the far right, but these days its role is greater than that.

Football now is how many places express their existence and their identity, so all enveloping that it is in effect another theatre of conflict. Some wear their club shirts to express violent far-right views; the evidence of Sunderland last weekend is that far more wear them to express an inclusive pride in their city.

• This article was amended on 11 August 2024. Sunderland’s average attendance for the 2023-4 season was 41,028, not 34,000 as an earlier version said.