1.d4 d5 2.c4 c6 3.Nc3 Nf6 4.e3 e6 5.Nf3 Nbd7 6.Qc2 Bd6 7.b3 A very solid line.
7...0-0 8.Be2 b6 9.0-0 Bb7 10.Bb2 Rc8 [10...Qe7 is the main move.]
11.Rfd1 c5 [11...Qe7 Likewise here.]
12.dxc5 Nxc5 13.cxd5 Nxd5 14.Bc4N [14.Nxd5 Bxd5 15.Qc3 f6 16.Qd4 Qe7 17.Bc4 Bxc4 18.Qxc4 Nb7 19.Qe2 e5 20.e4 Qe6 21.Rd5 Rc7 22.Rc1 Rfc8 23.Rxc7 Rxc7 24.h3 Bf8 25.Ne1 Rd7 26.Rxd7 Qxd7 27.Qc4+ Qf7 28.Qc6 Nc5 29.Ba3 Nxb3 30.Bxf8 Nd4 31.Qa8 Qxf8 32.Qxa7 Qb4 33.Qa8+ Kf7 34.Nf3 Nxf3+ 35.gxf3 Qc5 36.Qb7+ Kg6 37.Qd7 Kh6 38.a4 Qc1+ 39.Kg2 Qg5+ 40.Kf1 Qc1+ 41.Kg2 Qg5+ 1/2-1/2 Karpov,A (2619)-Anand,V (2788)/Corsica 2009]
14...Nb4 15.Qe2 Qe7 16.a3 Nc6 17.b4 Nd7 18.Ne4 Bb8 19.Ba6 Bxa6 20.Qxa6 Sometimes this kind of swap gives White some play against the weakened light squares, but it doesn't look too serious in this case - none of White's other pieces are ready to help the queen.
20...Nde5 21.Rac1 [It's worth considering the more patient 21.Ne1 (and I'm sure Caruana did consider it). Black will come visiting White's kingside anyway, e.g. 21...Ng4 22.h3 f5 23.Nc3 (23.hxg4 fxe4 is a little dangerous for White.) 23...Bh2+ 24.Kh1 (24.Kf1 Nxf2! 25.Kxf2 Qh4+ 26.Kf1 f4 27.Nf3 fxe3 28.Qe2 Ne5 29.Qxe3 Rxf3+ 30.gxf3 Qxh3+ 31.Ke2 Nc4 32.Qg5 h6 33.Qg4 Qxg4 34.fxg4 Nxb2=/+ ) 24...Nxf2+ 25.Kxh2 Nxd1 26.Rxd1 Ne5= /+=]
21...Nxf3+ 22.gxf3 f5 23.Ng3 f4= Initiating a tactical sequence resulting in a draw.
24.exf4 Bxf4 25.b5 Bxc1 26.Rxc1 Qf7 27.bxc6 Qxf3 28.Bd4 Rxc6 29.Rxc6 Qxc6 30.Qxa7 The minor pieces are better than the rook and pawn here, so Black should (and does) force the draw.
30...Qc1+ 31.Kg2 Qc6+ 32.Kg1 Qc1+ 33.Kg2 Qc6+ 1/2-1/2