As the final whistle blew on a bruising and barnstorming and brilliant evening’s entertainment, Ireland’s players wreathed each other in hugs: their ordeal finally at an end, their conquest complete. Johnny Sexton, their captain and talisman, was not among them. He had been withdrawn with a few seconds left on the clock, presumably to grant him one last valedictory ovation from a Twickenham crowd that may never see him in action again.

This is the sort of treatment Sexton should probably start getting used to over the coming months. Earlier in the week he finally ended months of speculation by revealing that his latest contract would be his last: a retirement announced 18 months in advance, taking him as far as the next World Cup in France. If the announcement itself was little surprise given that Sexton will be 38 by then and has already been fending off questions about his departure for half a decade, then there was also a certain curiosity to its timing.

Nobody does the long farewell quite like the Irish: the moving montages, the floral bouquets, the touching tributes. The former winger Shane Horgan jokes that during Rory Best’s extended retirement tour of 2019, Best’s son Ben ended up spending more time on the Aviva pitch than he ever did. Brian O’Driscoll also announced his retirement almost a year in advance and in a recent Off The Ball podcast identified another possible pitfall of the drawn-out retirement: the procession of “last evers”. Every game becomes your last at a certain venue, your last against a certain opponent, your last in a certain competition. The epilogue of your career unfolds against a background music of finality, loss and premature memorialisation.

Of course, you have to assume Sexton is too much of a professional to be affected by any of this. But perhaps it has an effect on how the rest of us see and talk about him. For Andy Farrell and the strategists of Irish rugby, there are plans to be tweaked, successors to be auditioned. Sexton may have declared his intention to “attack” the final part of his career. But somehow once you start the clock ticking, it becomes impossible not to start imagining the bomb.

There were times when you could almost sense Ireland beginning to process these questions in real time. Sexton didn’t have a bad game, as such. He had a relatively quiet game, which in many ways was hardly his fault. Even so he kicked his points, kept things ticking over, exerted an austere calming influence on the decisive final stretch during which Ireland finally picked England off. But there was also a distinct absence of high notes, long periods spent on the margins watching the game explode around him, the maestro conducting an orchestra that nobody could hear.

Johnny Sexton
Sexton kicked his points and kept things ticking over for Ireland. Photograph: Hannah McKay/Reuters

Afterwards Sexton talked about how Ireland’s famous cohesion was a product of their immaculate preparation, the exhaustive drilling of players already familiar with each other from the club game. Perhaps by contrast, Ireland’s struggles here sprang from a scenario they could scarcely have predicted, a game that unfolded in dazzlingly unfamiliar patterns. The early red card for Charlie Ewels added a note of chaos to a game already at high pitch, and as against 13-man Italy, here Ireland looked curiously scruffy and unsettled, seemingly in a rush to do everything at once.

There were handling errors, dropped passes, passes to nobody. The Irish pack lost its grip on the scrum early on and never really regained it. The absence of Andrew Porter and Rónan Kelleher was keenly felt. Sexton himself gave away a sloppy offside penalty by standing in front of the kicker. Ireland went into the half-time break 15-9 up, but still it felt like a battering, a retreat, a job made far harder than it needed to be.

Sexton did grow into the game a little as it went on. There was one artful little kick over the top for Andrew Conway to chase, some sharp passes to set up Ireland’s trademark round-the-corner attacks. Then of course, there’s the stuff few of us see: the little directions and asides, the words of encouragement, the messages and maxims that will have been hammered home in a thousand team meetings. Sexton is on that rarefied plane of athlete where even his mere presence can feel quietly decisive. Certainly Ireland fans are entitled to wonder how differently this championship might have gone had he been fit in Paris.

Even his late withdrawal, it turned out, had tactical rather than nostalgic motives. Afterwards Sexton explained that his 80th-minute curtain call was not some mawkish milking of applause, but a sly slice of gamesmanship. “I was walking off to try and drag some time out at the end of the game,” he said. “It [being my final game at Twickenham] wasn’t something that crossed my mind.”

And of course, any win at Twickenham is worth celebrating in its own right. Perhaps the fact that Ireland were able to win with their captain such a peripheral figure can be a source of encouragement. Perhaps, by contrast, it was a foretaste of a colder future. What happens when your big-game player fails to have a big game? What happens when a team is cast so thoroughly in one man’s image that it becomes hard to envisage life without him? The one consolation for Ireland is that they’ll have plenty of time to work it out.