Twenty days ago, on the eve of a world championship match that would prove more gruelling and arduous than many observers had expected, Magnus Carlsen described his forthcoming title defence against Russia’s Sergey Karjakin in pugilistic terms.

“For me, it’s a matter of when I get the chance, I’ll try to punch him until he finally knocks over,” Carlsen said.



Magnus Carlsen defeats Sergey Karjakin to retain World Chess Championship – as it happened Read more

For nearly three weeks, Carlsen tried and tried, but made little progress against the painstakingly resolute defensive play of his Russian rival, who time and again was able to salvage results from seemingly impossible positions.



But then on Wednesday, the 26-year-old Russian finally toppled to the canvas.



The world’s top-ranked player saw off his dogged challenger to retain his world title after winning Wednesday’s four-game rapid playoff with victories in the third and fourth games following draws in the first two.



There had been nothing to separate champion and challenger after 12 classical games in the purpose-built soundproof studio at the Fulton market building in lower Manhattan. The first seven ended in draws – with Karjakin coming back from the brink in the third and fourth – before the challenger drew first blood in the eighth. That left Carlsen more vulnerable than he had ever appeared during his three-year championship reign, with any false move all but precluding his hopes to retain.



Carlsen v Karjakin: it's sudden death in World Chess Championship Read more

But Carlsen, also 26, levelled the match with a stirring victory in game 10 on Thanksgiving Day, before a pair of draws set the stage for Wednesday’s four-game rapid match, in which each player had 25 minutes to complete his moves.



The players fought to a forgettable draw in Wednesday’s opener before Karjakin managed one last daring escape in the second game, clawing back to salvage a draw despite a wildly inferior position and a perilous time disadvantage.



Carlsen had missed a move that surely would have led to victory, a blunder that enabled Karjakin to escape with the tie-breaker series still level.



“I had all sorts of negative thoughts in my head,” said Carlsen, who will bring home 55% of the roughly $1.1m prize fund – and not the originally contracted 60% winner’s share – because the match went to a tie-breaker. “It was very difficult to settle down.”



But Carlsen, who is also the world’s top-ranked rapid player, recovered admirably playing as black in the third game. He build up positional and time advantages to pressure Karjakin, who resigned after an inexplicable blunder.



That left Karjakin in need of no less than win with the black pieces to keep his flickering title hopes alive. He opted for the Sicilian defence, to cheers from more than 600 spectators in the gallery, but couldn’t overcome Carlsen’s tactical aptitude and unwavering positional advantage. A queen sacrifice by the Norwegian caught the challenger’s king in a mating net, allowing the champion to finish off the championship defence in style.



It marked the first time New York had played host to a world title match since 1995, when Garry Kasparov retained his title against Viswanathan Anand on the 107th-floor observatory deck in the south tower of the World Trade Center.



A generation later, it offered a venue for a player regarded by some as the best ever to grind out a victory when he wasn’t as his best – the litmus test of any great champion.



“I’m very happy that at the end of the match I managed to find joy in playing,” Carlsen said. “Today, it was fun to play.”