19...Bc8 20.Ng4 (“I was kicking myself for not taking on b5 first” – Anand. Now Carlsen secures counterplay on the b-file ) 20...Nc5 21.Nh6+ Bxh6 (If 21...Kf8 22.Re3! and Rf3 with a very awkward pin) 22.Bxh6 bxa4 23.Ra2 a3! 24.bxa3 Nfd7 (24...Rb3 25.Bg5!) 25.f4 (The computer prefers Black here, whereas my human assessment is that Black’s position is critical) 25...a5?! (25...exf4 26.Qxf4 Qf6 27.Qe3 Ne5 makes a fight of it. Black can play Rb3 next) 26.Rf1 f6 27.f5! Nd3 28.Bxd3 cxd3 29.Qd1! Re7 30.Raf2 Rf7 31.Qxd3 Nc5 32.Qf3 Ba6 33.Qg4! (Black is lost – the attacking pieces outweigh the defenders and the knight is excellent at close quarters) 33...g5 (33...Bc8 34.Qh4 ) 34.h4 Bxf1 35.Rxf1 Qd7 36.hxg5 fxg5 37.Qh5 (Or 37.Bxg5 Rg7 38.Nh5 ) 37...Kh8 38.f6 Rg8 39.Bg7+ Rfxg7 40.fxg7+ Qxg7 41.Nf5!