Magnus Carlsen now leads the World Chess Championship final ©FIDE

Defending champion Magnus Carlsen produced the first victory of the World Chess Championship final in Dubai, outlasting Ian Nepomniachtchi to win a mammoth game.

It was the longest game in World Chess Championship history, lasting 136 moves and the bones of eight hours.

The experts' consensus was that Nepomniachtchi - competing under a Russian Chess Federation flag - had the advantage early on, and further looked in the ascendency when he took Carlsen's queen.

Yet the Norwegian took two rooks in the related moves, working his way back into the game and ultimately into a position where Nepomniachtchi, using the black pieces, had only his king and queen left.

From there, Carlsen was able to squeeze out a victory.

It is the first classic game in the final of the World Chess Championship to have a decisive result since Carlsen beat Russia's Sergey Karjakin in game 10 of the 2016 final - to draw level on that occasion.

Game seven of this year's final is due to be played tomorrow.

Fourteen are scheduled, plus a tiebreak if needed.

Carlsen is seeking to win the world title for the fifth time in succession, having held it since 2013.