Pawn and Two: Carl Schlechter in the Deutsche Schachzeitung, stated regarding 13.Qxb7: <If 13.Qxa8, then 13...Qxg2. nevertheless, the text move is inferior to 13.Rxd5.>
Fritz indicates that capturing the Queen would lead to an approximately equal position: (-.03) (22 ply) 13.Rxd5 Rxc8 14.Nf3 Nb4 15.Rd1 Nc2+ 16.Kf1.
The move 13.Qxb7??, gave White a lost position: (-4.42) (21 ply) 13.Qxb7?? Ba5+!
Fritz showed 13.Qxa8! to be White's best continuation, offering strong winning chances: (1.98) (22 ply) 13.Qxa8! Qxg2 14.Bd6 h5 (not 14...Qxh1? 15.Kf1 Qe4 16.Re1!), (2.13) (25 ply) 15.Rd3 Rh6 16.Bc7 Re6+ 17.Ne2 Qxh1+ 18.Kd2 (2.01) (25 ply) 18...f6 19.Bxd8 Qe4 20.Bc7+ Kf7 21.Rd7+.
At this point, although the ending is still very difficult, I believe White is winning after either: (2.11) (25 ply) 21...Ne7 22.Nc3 Qb4 23.Kc1 Re1+ 24.Kc2 Re2+ 25.Nxe2 Qa4+ 26.Kc1 Qxd7 27.Qd8 Qxd8 28.Bxd8 Nc6 29.Bc7, or (2.24) (25 ply) 21...Re7 22.Rxe7+ Nxe7 23.Qxa7 Qb4+ 24.Kd1 Qxb2 25.Qa4.
Alapin should not have played 12...Nc6??. Schlechter incorrectly gave 12...Nc6?? two exclamation points, stating: <This brilliant reply frustrates White's cleverly planned combination, beginning with 7.Qc2.>. Black's best move was: (.25) (21 ply) 12...Qe6! 13.Qxe6 fxe6, and after 14.Nh3, 14.Nf3 or 14.Ke2, White has only a very small advantage.