It was really essentially over after the spectacular ninth game that I mentioned, when Anand's all-out offensive failed in dramatic fashion, leaving him three wins down with three games to go, then yesterday they drew in game ten to officially end the match.
In some of the earlier games Anand also lost a potential win or a potential draw respectively by making some minor mistake, with Carlsen being so incredibly good at making the most of any opportunity and pouncing on any mistake however small. In this case, Carlsen should have been able to hold on for a draw with optimal play on both sides, but Anand made a really serious blunder, so bad that he just resigned one move later since Carlsen had made the right reply.
As I've seen some commenters argue, it's kind of sad how the prevalence of super-powerful chess engines has now created an atmosphere where human players are rarely said to have found a great move or winning move - the only moves that are commented on are the errors, the times when they select a move which computers have clearly shown to be inferior. Which is really an injustice to both players, since it makes it look as if Anand lost each of his lost games by blundering, while Carlsen merely had to sit back and profit from the blunder - that's seriously underestimating the brilliant play from both players in many of the games.