After 7 drawn games the 2016 World Championship sprung to life after Karjakin beat Carlsen in the 8th game. Once again Carlsen played a surprise opening as White (Colle-Zuketort) but the choice backfired on him as Karjakin built up a small advantage. However Karjakin passed up some aggressive choices in the middlegame, content to nurse a small advantage instead. Just before the first time control, Carlsen found a tactic to keep him in the game, and most of the commentators predicted another draw. Instead, Carlsen tried to push a little too hard and suddenly Karjakin spotted a winning line that involved a running 'a' pawn. Carlsen realised far too late he had no decent moves to save the ending and resigned on move 52.
This is the first time Carlsen has fallen behind in a World Championship match. With 4 games left to play he will need to find a way of creating more winning chances than he has so far in the match. Karjakin on the other hand can now continue his 'rope a dope' strategy, as the onus is on Carlsen to make the running. Of course the psychological aspect should not be overlooked, as sometimes taking a lead can disorient a player.
Tomorrow is a rest day, and I assume both Carlsen and Karjakin will be spending most of it planning a startegy for the last 4 games.