Missed chances

Magnus Carlsen has retained the World Championship but only after Sergei Karjakin, the challenger, missed some glorious opportunities.
In game 9 Karjakin, already a point ahead in the match, built up a formidable attacking position, only to miss the coup juste at the critical moment.
 
Karjakin-Carlsen, New York (Game 9) 2016
(see diagram 1)
 
In the diagram position, Karjakin played 39 Bxf7+ which fizzled out to a draw after 39 … Kxf7 40 Qc4+ Kg7 41 d5 Nf5 42 Bc3+ Kf8 43 Bxa1 Nxh4+ 44 Qxh4 Qxd5 45 Qf6+ Qf7. What Karjakin missed was 39 Qb3 when all the variations work in his favour, e.g. 39 … Nf5 40 Bxf7+ Kg7 41 Rh3 (forced) 41 … Qe7 (threatening …Nh4+) 42 Bg8 Nh4+ 43 Rxh4 Qxh4 44 Qf7+ Kh8 45 Qxc7 Kxg8 46 d5 which should win.
 
In the very next game, as Black, Karjakin overlooked a move which would have forced a draw, thus leaving him still one point ahead with two games to play.
 
Carlsen-Karjakin, New York (Game 9) 2016
(see diagram 2)
 
From the diagram, Karjakin chose 21 … Ng5 and was eventually ground into the dust after a long endgame. However, he could have drawn with 21 … Nxf2+. After 22 Kg2 (22 Kg1 Qg5 is fine for Black as he has 23 Qxg5 Nh3+) 22 … Qf7 and now 23 Qe2 is met by 23 … Nh4+. 23 Kg1 instead appears very strong but is met by 23 … Qf6! 24 Qe2 Nh3+ 25 Kg2 Nhf4+. So, after 23 … Qf6 White must settle for 24 Kg2 repeating the position.
 
Karjakin-Carlsen, New York play-off (Game 3) 2016
(see diagram 3)
 
Finally, in game 3 of the play-off, occasioned by the 6-6 score in the main match, Karjakin succumbed after blundering with 38 Rxc7?? Ra1 White resigns. Instead 38 Rb1, driving away the black queen, leaves all to play for.
 
When fortune smiled on the champion in the fourth game of the playoff, he did not hesitate to seize his chance. White’s concluding move (see this week’s puzzle) must have been the most dramatic move ever played to win a World Championship.