This move from game 5 was more crucial, since it led to the first decisive game of the match. Carlsen had a slight advantage in the endgame and in his typical style, he kept putting pressure and taking advantage of small inaccuracies by Anand until he got the full point.
Among a set of inaacurate moves, this is likely the most critical, as Anand with black played 45. ... Rc1+ and lost. Instead, 45. ... Ra1 capturing the a-pawn should be good for a draw.