If this is Guardiola's farewell trophy, then Semenyo is the fitting hero

The striker doesn't fit the stereotype of a classic Pep signing, but we've all come a long way over Manchester City's decade of success. One way or another, this was always going to be Pep's day. At the final whistle, Pep Guardiola didn't punch the air; in fact, he barely celebrated. Instead, he walked slowly towards the scorer of the only goal, Antoine Semenyo, patted him vigorously three times on the backside, then drifted around the edges of the bouncing groups on the Wembley pitch.

There will be a temptation to read signs into this. Nobody truly knows if Guardiola will leave Manchester City at the end of the season. The contract renewal mind games are nothing new, though perhaps not with so many whispers of departing assistants and leaked succession plans. But the thoughtful stroll was typical.

One of Guardiola's many quirks is that even in victory, he often seems slightly disappointed that the match – that glorious torment – is already over. Do what you love, and you'll never work a day in your life. Do something that grips you with skull-scratching, trouser-ripping energy, and you'll never quite lose that vital spark – right up to the end of his 591st game, his 416th win, and his 15th major trophy.

Guardiola was the familiar frenetic spectacle throughout this FA Cup final. Dressed for the occasion in a vanilla yak-wool polo neck and country-gentleman-style trousers – looking like a minor royal cousin visiting a school – he was in his technical area from the start, hands swirling in those furiously stylized patterns, like someone trying to break the world record for assembling an invisible flat-pack wardrobe.

If this truly is his last major touchline moment, it would be fitting for it to come at Wembley – with a third FA Cup, an eighth domestic knockout trophy, and a 12th medal won at this stadium, if we include the Community Shield and Barcelona's Champions League triumph. It's often said that Guardiola is commendably and respectfully obsessed with England's domestic cups. Is it respect? Or simply an all-encompassing obsession with winning? You suspect he'd be just as "respectful" of a game of Connect 4 with his niece on Boxing Day, or trying not to step on the pavement cracks on the way home.

But this was a good day for Pep in many ways. City started the match without true creativity in midfield but changed things at halftime by bringing on Rayan Cherki. The decisive second-half goal came from a player signed in January precisely for such a moment. It was created by Erling Haaland, who received the ball deep, spun behind the defense for a return pass from Bernardo Silva. Semenyo guided Haaland's cross with his right foot into the corner with the inside of his heel.

Semenyo was a fitting winner in a Cup final – a player who has trodden his own singular, pyramidal path to this moment: from Bristol to Bath, Newport, and Sunderland. This goal will seal the success of his transfer, which still seems slightly odd in the broader context. Semenyo is a crucial player. But he's not elite in Pep's classic mold. He's not hyper-technical. His touch is sometimes clumsy. He doesn't seem pathologically obsessed with possession. Pep wouldn't have signed this man 10 years ago.

But we've all come a long way in that regard. Even the agent of change is changed by the very act of changing. A decade ago, it would have seemed unexpected for the great modernizer, the duke of elite Iberian style, to become so deeply intertwined with the FA Cup. To this day, this annual Wembley date seems like a perfect embodiment of Guardiola's status both as an outsider – the systemic brain who doesn't coach slide tackles – and as the greatest structural influence on how football is played in England today. The navigator of City's pirate ship, with 115 charges, suing the league to its foundations, yet deeply embedded in the traditions of English football – a singular guardian of the domestic cups.

Now, there's always a slight sense of tenderness on such occasions. Here it is, the dear old Cup, still going through its moth-eaten rituals. Still the marching band? Still the tin trophies and bedsheet banners? Still Ronnie Radford? The orchestra was smartly buttoned up. The soldiers and sailors diligently folded their tarpaulins. "Abide With Me" was sung by a Bradford City choir – one of English football's great moments, a reminder of the sport as collectivism, connection, geographical belonging, relief from industrial life.

It's simply a wonderful hymn, partly because it's not about victory or triumphalism. It's about death and solace, about glory of a more eternal kind, about the ultimate meaninglessness of material things. Speaking of which – here are Manchester City and Chelsea, dual expressions of two different forms of sporting excess. On one side – a state propaganda project. On the other – hedge fund football, a bet on a global entertainment product. And in the middle – waste, excess, polishing the image of a harsh regime, the legacy of a Kremlin-linked oligarch.

And yet, of course, there is still glory here, even in a match like this, which began with 45 minutes of anti-football. For a long time, Chelsea did practically nothing. Understandably so. At the moment, it feels like a club where everyone constantly wants to leave – like some terrible rooftop party where people are constantly checking their phones, muttering about exits, and waiting for their car to arrive.

Still, it was a good day for Callum MacFarlane, who arrived here in a tracksuit, hoodie, and big white trainers – like someone caught on their way to buy a Snickers from a Tesco petrol station. To his credit, Chelsea started to wake up after the break, with Cole Palmer looking sharper on the right. But it always felt like City would have enough. Their reserves were too strong, their manager – too good at this. From here, City can still finish with a domestic treble, though at no point did they truly look like a team marching towards one of the greatest English seasons.

As always, their second-half resurgence was driven by a willingness to spend money. This is the central tension in Guardiola's own career – the desire of some to see only the advantages, the money spent, the elite players, and to ignore the reality that this is simply where the greatest coach in the world works.

In the end, Guardiola was still entirely his old self. He said the FA Cup was "cool." He complained with genuine passion about the state of trains in Northern England. He promised that no one would be celebrating yet. City might not have the title in their own hands. But you wouldn't rule out another victorious stroll in a week's time.

Commentary by Barney Ronay for "The Guardian"