There was a moment on Sunday morning when, scrolling through pages of content celebrating the New York Knicks’ spectacular NBA championship win in the city – videos in which it seemed people of every age, race, background and zip code put aside their differences to hug and scream – I wondered how far the principle of sport-as-the-ultimate-leveller might stretch.

For example: given the joy on Saturday night was so intense, could you have sent the most hated figures in the US into the ecstatic Knicks viewing parties – those gatherings of thousands who came together to watch the game projected on to the sides of buildings – and witnessed the joy of the event transform them into regular humans? Greg Bovino, say, the loathed former US border tsar in his soldier-of-fortune Halloween costume – pop a jaunty Knicks cap on his head and might he elicit high fives? What about ICE agents in Knicks jerseys? I tried to imagine Elon Musk – a man who has surely never thrown, caught or enjoyed watching a ball in flight in his life – attending a Knicks party and experiencing, possibly for the first time, a group of people who appeared genuinely pleased to see him.

There’s no knowing. All I know is that on Sunday morning, the stories started trickling in from New York of a once-in-a-lifetime experience. A friend, out in Manhattan with a bunch of nerdy podcasters, pulled them into a bar for the tail end of the game and gave them the best night of their lives. My children’s 13-year-old half-brother was out on the streets of the city celebrating until 1am. Video after video – of air traffic controllers at JFK airport saying “go Knicks” at the end of dispatches giving permission to land; of people on those planes celebrating as every screen on board was tuned to the game; of Metropolitan Transportation Authority employees losing it on the subway and buses – captured a truly rare moment of city-wide unity.

The scenes reminded me of Barack Obama’s first presidential win in 2008 when, briefly, everyone in New York felt as if they were on the same side. I was in Harlem that night and people came out into the streets to bang pots and pans and hug strangers. And so it was this past weekend, when even the grousing was good-natured.

Hard on the heels of Saturday night’s celebrations was the inevitable audit by sports pundits of real v fake celebrity Knicks fans. I wasn’t in New York for any of this, which makes me one of those creeps getting in on it from afar. Ben Stiller copped it (“he gets [the tickets] for free – it’s a joke!”), as did Taylor Swift for supposedly being a fake fan. Only one front-row celebrity, Spike Lee, seemed to pass muster for being a paying season-ticket holder.

Meanwhile, Zohran Mamdani, who to that point had been fiercely dividing New Yorkers, emerged from the finals as everyone’s hero. The mayor of New York’s political acuity – signing an executive order suspending bedtimes for kids across the city for as long as the Knicks were in the finals; popping up in bars, wearing his team strip over his shirt and tie – was as on display as his sports fanaticism.

Mamdani is also an Arsenal fan, and comparing the Knicks’ championship win with Arsenal’s Premier League triumph last month showed up interesting differences between the two cities. The Arsenal victory was grungier, possibly boozier and, although just as inclusive as the Knicks hysteria, light on the myth-making that went on at the weekend. North London might be mentioned in some of the Arsenal chants, but nothing on Earth celebrates itself the way New York does – less a distinction between Arsenal and Knicks fans than between Americans and Britons.

Anyway, for a brief moment it was heaven, despite the people trying to extract teachable moments from the Knicks win by asking how we might use this spirit of togetherness in the future. (We can’t; it’s ephemeral, that’s the whole point of live sporting events and, by the way, stop trying to turn everything into homework.)

By law, any big sporting victory must be compared to historic euphoric events. In this case, scenes from New York at the weekend made me think of the Christmas armistice during the first world war. It’s an alternative reality that will return to the city on Thursday, when the Knicks victory parade makes its way up Manhattan to City Hall and strange scenes will unfold. People will talk to each other on the subway; the crowd noise will be heard in New Jersey; the NYPD will receive hugs off passing New Yorkers who would otherwise dismiss them as Trump supporters from Staten Island. It will be beautiful – and then, by the nature of these things, it will be gone.

• Emma Brockes is a Guardian columnist