Magnus Carlsen has all but retained his world title after defeating Russia’s Ian Nepomniachtchi for the third time in four games in the ninth encounter of their showdown on Tuesday in Dubai, opening a commanding 6-3 margin in the best-of-14 match with five contests remaining. The cracks that have emerged in the challenger’s veneer since Carlsen drew first blood with a psychologically taxing 7hr 45min epic on Friday – the longest game in the recognised 135-year history of world championship matchplay –culminated in a spectacular self-destruction on Tuesday as Nepomniachtchi made an extraordinary blunder in the middlegame that immediately pointed his Norwegian opponent towards a straightforward win in just under four hours. “Pressure gets to everybody,” the 31-year-old Carlsen said afterwards. “As I said before, no style points awarded. I’ll take it. It was a tough game in which I was under pressure both on the board and on the clock. Just to turn it around like that was unexpected.” Nepomniachtchi, playing with the favourable white pieces, arrived at the Dubai Exhibition Centre having shorn off his signature man bun on Monday’s rest day and started things off with a fresh opening to match his remade appearance. Opting for an English (1 c4) after playing the closed Ruy Lopez in each of his previous four white games, the Agincourt Defence followed (1 ... e6 2 g3 d5 3 Bg2) before the position entered rare territory after only five moves (4 ... Nc6 5 O-O Bc5). The position quickly transposed into a more mainstream line (6 d3 Nf6). But after 7 Nbd2 a5 8 Nb3, Carlsen found himself more than 20 minutes behind on the clock facing a complex position with no easy solutions. Nepomniachtchi’s first buckle came with 15 bxa3, which failed to press his early advantages by allowing Carlsen to recapture immediately and avoid the forced lines of the alternative. That he made the move in less than five minutes while enjoying more than a half-hour edge on the clock will only stoke a recurring criticism throughout this match: that he has been too hasty and impatient in the crucial moments. Chess engines tracking the game evaluated the position as dead even over the next series of moves though Nepomniachtchi appeared to have the better attacking chances with a mounting time advantage. The queens came off the board after Carlsen played the predicted 24 Qxe1+ and Nepomniachtchi recaptured (25 Rxe1), followed by 25 ... h5 26 Bxb7 Ra4. That was when Nepomniachtchi missed an elementary tactic with 27 c5?, a sensational blunder which trapped white’s bishop and sealed his doom. Carlsen, visibly relieved by the stroke of good fortune, took less than three minutes before playing the natural 27 ... c6. “You work a whole lifetime for one shot and this is what happens on the biggest scene,” the three-time British champion David Howell lamented from the commentary booth. “He’s probably never blundered like this in his whole career. It’s just so sad.” Within the hour it was finished after Nepomniachtchi resigned following Carlsen’s 39th move, ending his suffering after 3hr 51min. In the immediate aftermath Nepomniachtchi confessed he did not realise 27 c5 was a costly move until after Carlsen’s response. “Till [27 ... c6] was played I was quite happy,” he said. “Just some insanely bad luck. “I couldn’t imagine there is actually a way which exists to blunder in this position. The position was somewhere between slightly better and much better during most of the game ... It’s even funny there’s a way to blunder this position in one move. Who could know?” Entering the ninth game on Tuesday, the 31-year-old Nepomniachtchi was attempting to become only the third player in the centuries-spanning annals of world championship matches to win after trailing by two or more points. The others were Max Euwe, who trailed 5-2 against Alexander Alekhine before winning 15½-14½ in 1935, and Bobby Fischer, who trailed 2-0 against Boris Spassky before winning 12½-8½ in 1972. The task is that much taller after the shocking finish on Tuesday . Asked his thoughts on the state of the match with five games to go: “It’s worse than I expected.” Carlsen said the satisfaction of earning a win through hard work far exceeds having it handed to you by an opponent, but stopped short of expressing sympathy for his flailing opponent. “It’s the world championship,” he said. “Basically, you prefer to beat an opponent who’s playing at his very best. But if he’s not, you take it any day of the week.”