Kasparov's 7...h6? in the game below causedcost him the game and the match, and later Kasparov accused Deep Blue team of cheating.
[FEN ""]
[Event "IBM Man-Machine"]
[Site "New York, NY USA"]
[Date "1997.05.??"]
[EventDate "?"]
[Round "6"]
[Result "1-0"]
[White "Deep Blue (Computer)"]
[Black "Garry Kasparov"]
[ECO "B17"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "37"]
1.e4 c6 2.d4 d5 3.Nc3 dxe4 4.Nxe4 Nd7 5.Ng5 Ngf6 6.Bd3 e6
7.N1f3 h6 8.Nxe6 Qe7 9.O-O fxe6 10.Bg6+ Kd8 11.Bf4 b5 12.a4
Bb7 13.Re1 Nd5 14.Bg3 Kc8 15.axb5 cxb5 16.Qd3 Bc6 17.Bf5 exf5
18.Rxe7 Bxe7 19.c4 1-0
https://www.chessgames.com/perl/chessgame?gid=1070917
I would also like to suggest a move from a final game of the tie-break in Kramnik - Topalov from classical-Fide championship unification match in 2006. With 44...Rxc5 Topalov went from difficult position to instantly losing. The match was full of controversy if this is what you are looking for.
[FEN ""]
[Event "Kramnik - Topalov World Championship Match"]
[Site "Elista RUS"]
[Date "2006.10.13"]
[EventDate "?"]
[Round "16"]
[Result "1-0"]
[White "Vladimir Kramnik"]
[Black "Veselin Topalov"]
[ECO "D47"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "89"]
1.d4 d5 2.c4 c6 3.Nf3 Nf6 4.Nc3 e6 5.e3 Nbd7 6.Bd3 dxc4 7.Bxc4
b5 8.Be2 Bb7 9.O-O Be7 10.e4 b4 11.e5 bxc3 12.exf6 Bxf6
13.bxc3 c5 14.dxc5 Nxc5 15.Bb5+ Kf8 16.Qxd8+ Rxd8 17.Ba3 Rc8
18.Nd4 Be7 19.Rfd1 a6 20.Bf1 Na4 21.Rab1 Be4 22.Rb3 Bxa3
23.Rxa3 Nc5 24.Nb3 Ke7 25.Rd4 Bg6 26.c4 Rc6 27.Nxc5 Rxc5
28.Rxa6 Rb8 29.Rd1 Rb2 30.Ra7+ Kf6 31.Ra1 Rf5 32.f3 Re5 33.Ra3
Rc2 34.Rb3 Ra5 35.a4 Ke7 36.Rb5 Ra7 37.a5 Kd6 38.a6 Kc7 39.c5
Rc3 40.Raa5 Rc1 41.Rb3 Kc6 42.Rb6+ Kc7 43.Kf2 Rc2+ 44.Ke3 Rxc5
45.Rb7+ 1-0
