patzer2: <luzhin: Actually, there were two huge blunders by Eljanov, both with the same piece.> Yes Indeed!
White misses a sure win with <52. Re2?>, allowing Black a level position after 52...Ne3 = (0.00 @ 35 depth, Stockfish 8.)
Instead of <52. Re2?>, Stockfish 8 indicates White has at least three winning alternatives, including 52. Kf1 (+5.82 @ 35 depth,) 52. Kd1 (+4.50 @ 35 depth,) or 52. Ra2 (+4.45 @ 35 depth.):
( [Stockfish 8 64] 35:+5.82 52.Kf1 Ne3+ 53.Ke2 Nc4 54.Rd3 Nb2 55.e7 Kf7 56.Rb3 Rxd4 57.b6 Rd7 58.e8=Q+ Kxe8 59.b7 Re7+ 60.Kf1 Rxb7 61.Rxb7 Nc4 62.Ke2 Nd6 63.Rb6 Ke7 64.Kd3 Kd7 65.Kd4 Ke6 66.Ra6 Ke7 67.Ke5 Nc4+ 68.Kf5 Nd2 69.Rxh6 Nxf3 70.Rh7+ Ke8 71.Ra7 Kf8 72.Kf6 Kg8 73.Ra3 Nd4 74.Rd3 Nc6 75.Kxg5 f3 76.Rxf3 Nd4 77.Rf6 )
( [Stockfish 8 64] 35:+4.50 52.Kd1 Rd8 53.Ke2 Ra8 54.Rb2 Nb6 55.Rc2 Nd5 56.Rc5 Ke5 57.Nf5 Ra2+ 58.Ke1 Kxe6 59.Nxh6 Nb4 60.Rxg5 Nd3+ 61.Kf1 Ne5 62.Rf5 Ra1+ 63.Ke2 Ra2+ 64.Kd1 Nxf3 65.Rxf4 Ng5 66.Rb4 Ra7 67.Nf5 Rb7 68.b6 Nh7 69.Ke2 Nf6 70.Kf3 Nd5 71.Rb5 Nxb6 72.g5 Rd7 73.g6 Nc4 74.Kg4 Kf6 75.g7 Kf7 76.h6 Rd3 )
( [Stockfish 8 64] 35:+4.45 52.Ra2 Nc7 53.Ra7 Nxe6 54.Nf5 Rd5 55.Ra6 Rd3 56.Rb6 Ke5 57.Nxh6 Nd8 58.Ke2 Re3+ 59.Kf2 Rb3 60.Rg6 Rb1 61.Rxg5+ Kf6 62.Rg6+ Ke5 63.Ke2 Ne6 64.Nf5 Nf8 65.Rg8 Nh7 66.Rg7 Nf8 67.Rb7 Ne6 68.h6 Ng5 69.Re7+ Kf6 70.h7 Rh1 71.b6 Rh2+ 72.Kd3 Rxh7)
After missing the win with <52. Re2?,> White throws away drawing chances with <54. Rd2??,> allowing the winning Knight fork combination 54...Rxd4 55. Rxd4 Rxd4 56. Nc7+ -+ (mate-in-28, Stockfish 8 @ 51 depth) or the win of a piece after the game continuation 54...Rxd4 55. Rb2 Rd7 -+ (-5.31 @ 34 depth, Stockfish 8.)
Instead of 54. Rd2??, White can secure a level position with 54. e8=Q+ Kxe8 55. Rxe3+ fxe3 56. Nf5 = (0.00 @ 45 depth, Stockfish 8) or 54. Rxe3+ fxe3 55. e8=Q+ Kxe8 56. Nf5 = (0.00 @ 45 depth, Stockfish 8.)
P.S.: I use games like this to encourage my young Grandsons when they miss wins or draws in their tournament games. I tell them everyone makes mistakes in Chess, even the very best players. The important thing is to learn from our mistakes, so we can improve and avoid similar mistakes in the future.