wwall: 61.Qd6+ Kb7 is a three-fold repetition of the position, so it should have been a draw.
Instead of 66.Qa8+, White had a perpetual check after 66.Qc8+. Black can't play 66.Kd5? 68.Qg8+ Kc5 (67...Qe6?? 68.Nc7+) 68.Qxb3, winning th knight. So Black must play 66...Kb6 67.Qd8+ Kc5 68.Qc8+ and draw.
Instead of 68.Kh3, perhaps 68.Kg1 Qe3+ 69.Kg2 Nd2 70.Qd5+ Ke7 71.Qd6+ Kf7 72.Nd4 with more resistance.
Instead of 70.Qb7+, perhaps 70.Qh8 Qf6 71.Qh7+ Qf7 72.Qh4+.
Instead of 72.Qf2, perhaps 72.Qb7+ Qf7 73.Qb6 Qd7 74.Nd6.
Instead of 73.Qa7+, perhaps 73.Qb6 Nd2 74.Qa7+ Kh6 75.Qf2 Ne4 76.Qe3+ Ng5 77.Qxe5 Nf3+ 78.Kg2 Nxe5, but this probably wins for Black.
Instead of 74.Qf7, perhaps 74.Qf2+. If 74...Nc5, then 75.Nd4 Ne4 76.Qf8+ Kh7 77.Qf7+ Qg7 78.Qxg7+ Kxg7 79.Nb3 Nc3 80.Kg2 Nxa4 81.Nf3 may draw. Stronger for Black may be 74...Qh5+ 75.Kg2 Qd5+ 76.Kg1 Qd1+ 77.Kg2 Qd2 78.Nd6 Qxf2+ 79.Kxf2 Nc5, threatening 80...b3.
Instead of 77.Qxe3, if 77.Qf7??, then 77...Nf3+ 78.Kg2 Qe2+ 79.Kh3 (79.Kh1 Qh2 mate) Ng5 mate.
Instead of 79...Kg5, 79...g5 looks stronger.
Instead of 82...Ke3, stronger seems 82...g5+ 83.Kh5 (83.Kh3 Ke4) 83...Ne5.
Instead of 85.Kf6, if 85.Nc5, then 85...Ne5+ 86.Kf5 Nxg4! 87.Kxg4 b3 wins.