J.A. Topfke: The crucial error was 15…Qa5?!. Tartakower steps out of the pin and into the fire by removing one of the defenders of the critical square c6. An immediate attack on the weak point follows with 16.Ne5. 16…cxb5 17.Bxb5 Rd8 (or 17…Rc8) 18.Be8! Rxe8 19.Qxb7 Nd7 20.Qxd7 Qxa3 21.Qxf7+.
Rubinstein increases the pressure with 17.Rc5, but he could have taken the pawn immediately: 17.bxc6 Ba6 (17…Bxc6?! 18.Rc5 and White will form a battery on the c-file) 18.c7!? Nxc7 19.Bd6 Bxd4 20.Qxd3 Nba6 21.Nc6 Qb6 22.Ne7+ Kh8 23.Rc6.
17…Qc7 18.Qc2 g6 19.bxc6:
A)19…Bxc6? 20.e4 Nd7 21.Nxc6 Nbxc6 22.d5 exd5 23.exd5;
B)19…Nxc6?! 20.Nxc6 Bxc6 21.Rc1;
C)19…Ba6 20.e4 Nf4 21.Bc4 Bxc4 22.Rxc4
Relatively best, according to the computer evaluation, was to let White take the pawn: 18…Rc7 19.bxc6 Ba6 20.Be4 Nf6 21.Bf3.
20.Qxb5? Ba6 21.Qb1 Bxd3 22.Qxd3; 20.Bxb5!? Ba6 21.Bxa6 Nxa6 22.Qb7 Ndc7 23.Nc6 Qd7 24.Ne7+ Kh8 25.Bd6! Qd8 (25…Qxd6? 26.Qxa8+! and mate in three) 26.h4 Ne8 27.Bg3 h6 28.Rc6 Nb4 29.Qxb4.
An alternate, though more complicated, win was shown by the computer: 22.Qc5+ Ne7 23.Qxb4 Na6 24.Qb2 Rb8 25.Qe2 (25.Bxe7+ Qxe7 26.Qxb8+! Nxb8 27.Rxc8+ Qe8 28.Rxb8! Qxb8 29.Nd7+) 25…Qe8 26.Qh5.
Perhaps Rubinstein was in time trouble because Tartakower continues to play a piece down, though I suppose there are some back rank mate possibilities as well as queening threats.
29…Qb7 30.Nc6 Qd7 31.Qxd5!? Qxd5 32.Ne7+.
After 33.Nxf7! it is all over because 33…Rxf7? is answered by 34.Rc8+ Qf8 35.Rxf8+ Kxf8 36.Qd8#.