The black Queen is a monster, forcing the overloaded white heavy pieces to work overtime: the white Queen has to protect the pawn on f2 and the Rook must guard the square g2. The Knight is too far away to help the white King. You can almost hear the thunder and the computers come up with it in no time.
31...Ra1!! A double-deflection! This piece of chess tactics is seen rarely and one would not expect it in blitz games where steady play, not flashy moves, is rewarded. Black threatens to exchange the Rooks and mate on g2, and Carlsen cannot do anything about it. [But Karjakin, probably seeing only a single deflection of the white Queen, missed it here and on two following moves. He also could have returned to it later in the game, throwing his Rook to different squares along the first rank. Instead, he played 31...Kg7?! 32.cxd5 cxd5 33.b4 Rb8 34.Na6 Rb6 35.Nc7 Rxb4 36.Qa2 Ra4 37.Qb2 Ra5 38.Ne8+ Kg6 39.Nc7 h5 40.Qc2 Kh7 41.Qb2 Qf6 42.Rc1 Qf3 43.Rg1 Qf5 44.Rc1 Ra7 45.Ne8 Qf3 46.Rg1 Ra6 47.Qc2 Re6 Carlsen resigned. Finally, Karjakin was able to make the Queen deflection work: 48.Nc7 runs into 48...Rc6! picking up the Knight.]
32.Qxa1 [32.Rxa1 Qg2# ]
32...Qxf2+ 33.Kh1 Bf3+ mates. 0-1