The agate type will show that Magnus Carlsen retained the world championship he’s held for eight years by defeating Russia’s Ian Nepomniachtchi for a fourth time in six games on Friday, closing out their best-of-14 encounter by a score of 7½-3½ and bolstering his claim as the greatest player of this or any other era.

But the Norwegian’s fifth world title match victory – one short of the suddenly imperilled all-time record of six – was freighted with additional meaning by striking a decisive win for a sport that has been dogged by existential questions over its own relevance in an age of supercomputers said to have made the world’s top grandmasters too good to fail.

Related: Magnus Carlsen retains world chess title after final Ian Nepomniachtchi blunder

The familiar hand-wringing was impossible to ignore in the early stages of the €2m showdown between Carlsen and Nepomniachtchi that unfolded over the past two weeks in Dubai. Not only did they play to five straight bloodless results to open the proceedings – extending a record streak of 19 draws in classical world championship games extending back to Carlsen’s final two with Sergey Karjakin in 2016 and all 12 against Fabiano Caruana in 2018 – but engines evaluating the moves indicated it was to that point the most accurate title match in the event’s 135-year history.

For years observers have bemoaned the recession of humanity of a sport that has increasingly – and never more than in the generation since Deep Blue v Kasparov, 1997 – become informed by the machinelike objectivity of the supercomputer. Once again a parade of draws borne from near-perfect chess was threatening to overshadow the sport’s biggest spectacle, prompting renewed calls to revamp the format, including shorter time controls that might induce the world’s best players into the types of mistakes that make decisive results possible.

All of that went silent with game six, a heart-pounding psychodrama worthy of the sprawling canvas only the classical format can provide: two world-class players going toe to toe over eight gruelling hours within the lonely confines of a sound-proof glass box.

Nepomniachtchi went from having Carlsen on the ropes under clock pressure at the first time control, to coming within five seconds of losing on time himself, to finding himself squeezed toward submission in a positional endgame by a relentless foe operating with engine-like precision as Friday turned to Saturday until finally giving in with an inaccuracy on the 130th move. When the Russian resigned after midnight and the curtain dropped on the longest game ever played in a world title match, the playing hall erupted in applause.

It was a contest of extreme cognitive, emotional and physical intensity – and Carlsen admitted that dragging his opponent into deep waters, making it a test of endurance and stamina as much as skill, was in his plan. “Part of it was by design at some point,” he said. “I thought I should make the game as long as possible so that we would both be as tired as possible when the critical moment came. That turned out to be a good strategy.”

For Carlsen, who turned 31 last week and is regarded as no worse than the third best player in history with Kasparov and Fischer, it was a legacy-defining affair: perhaps the one game from thousands that will be invoked when his career is finished as emblematic of what made him different.

Carlsen’s preternatural ability to spot harmony where others see chaos, to build pressure over time, to hold nerve and never give, to take every infinitesimal advantage given and grind out wins from seemingly dull positions that appear bound for draws – to squeeze blood from a stone – has been the Norwegian’s calling card from when he first came to prominence in the early aughts as a fresh-faced, precocious teenager breathlessly touted as the “Mozart of chess”.

To accomplish it in his competitive prime on the biggest stage of all, in one of the rare moments every few years when this cloistered sport asks the public to lean forward and pay attention, elevated it from simply a memorable game to one of the greatest ever played.

“There’s only one player in the world against whom Ian would have lost this game today,” said Viswanathan Anand, the former champion turned commentator who ceded his title to Carlsen in 2013. “Unfortunately for him, that player was sitting opposite. Because as late as move one hundred and something, Ian still had the draw. But this guy just wouldn’t stop and that’s the reason he won.”

Further, game six embodied a triumph for a classical format dismissed as hidebound and obsolete by laying bare a human frailty that no amount of backroom technological advances can fully subsume. Grandmasters, like prizefighters, are avatars for wills. And the weeklong unravelling that ensued once Nepomniachtchi’s was shattered, while frankly difficult to watch, offered heightened gladiatorial drama no less panoramic and compelling than a five-set war of attrition at Wimbledon or the rare championship boxing match that ennobles both men while taking something out of one he may never get back.

The careless blunder that cost him in the eighth game was unbecoming of a player ranked in the world’s top five, which he is. The even more elementary gaffe that donated Carlsen the ninth, extinguishing his already threadbare comeback hopes, was among the most egregious in the annals of world championship matchplay. As Carlsen had said only days before: “Pressure gets to everybody.”

The flailing challenger, bruised by self-doubt and unable to even pinpoint how exactly it had gone wrong, punctuated his self-destruction with yet another extraordinary pawn blunder in Friday’s 11th game, gifting Carlsen the match. The margin of four wins and no defeats is the most lopsided result in a world championship since Capablanca’s triumph over Lasker exactly 100 years ago.

Carlsen will now keep the title for another year and a half before he is required to defend it in early 2023. The eight-man candidates tournament to determine his next challenger happens next summer. Nepomniachtchi will be there, though many believe Carlsen’s stiffest test could come from Alireza Firouzja, the teenage prodigy ranked second who punched his ticket after winning last month’s Grand Swiss in Riga.

For today, though, the winner is chess itself, which endures into tomorrow as it has for centuries, arresting imaginations across all cultures with the unceasing promise of infinite potential: all of it within those 64 tiny squares that contain more possible games than atoms in the observable universe. If there’s anything the past fortnight has shown – from the dizzying heights of Carlsen’s epochal game six win to the unpleasant denouement of his foil that followed – it’s that maybe there’s something still intrinsically human in this after all.