Rapport missed a much better move! He played 10..RxB+ which Stockfish rates as +1.16, not so very good for Black!

He should have played Nxd5! After cxd, black’s bishop picks up knight and rook on the long diagonal. Black gets R, N, P for N, B. Stockfish rates this move as -2.80.

Eventually, Carlsen gives back the exchange with 34. RxN+ and goes on to win.

I checked the chessgames database. The position after 10.Be3 has been reached 273 times before. The most common next move is 10..Bh6. The move Nxd5 is not in the database at all! You’d think someone would have seen this combination before.

Stockfish rates 10.Bh6 as only +.67 after 11. O-O and just +.45 after 11.Qd2.

I am very surprised no GM has seen 10Nd5 before. The bishop springing forth to pick up pieces on the long diagonal is not what you would call an obscure tactic. It’s the primary reason for Fianchetto in the first place!

Best move, Stockfish
1) -2.80 (26 ply) 10...Nxd5 11.cxd5 Bxc3+ 12.Bd2 Bxa1 13.Qxa1 Nd7 14.Bc3 b6 15.h4 Ne5 16.Nxe5 dxe5 17.Bxe5 f6 18.Bxf6 Qxd5 19.Bh8 Re7 20.Qc3 Be6 21.O-O Rd7 22.Bc2 Qc4 23.a3 Qxc3 24.Bxc3 Rad8

As played
1) +1.16 (22 ply) 11.fxe3 Qe7 12.O-O Nbd7 13.Qe1 Nh5 14.g4 Ne5 15.Nxe5 Bxe5 16.Rf3 Nf6 17.Qf2 Bxc3 18.Rf1 Be5 19.Rxf6 Bxf6 20.Qxf6 Qxe3+ 21.Kg2 Bxg4 22.Qxf7+ Kh8 23.Qf6+ Kg8 24.hxg4 Qxd3

Stockfish analyzed the wrong position! It forgot about the pawn on b2. After 11..Bxc3+, 12.bcc! End of story.

Here is the image from the Stockfish analysis. Where did Stockfish put the pawn on b2????? Compare the game image on move 10. I took a screen shot of the Stockfish analysis but don’t know how to paste an image here.

In any event, 10..Nxd5 is no good for black.

click for larger view

In my line of work, I tell people if you’re going to make a mistake, make it an interesting one. I’d call this an interesting mistake.