1.c4 Nf6 2.Nc3 e5 3.Nf3 Nc6 4.g3 Bc5 [4...Bb4 and 4...d5 are more frequently seen but this is respectable.]
5.Bg2 d6 6.0-0 0-0 7.d3 a6 [7...h6 , to prevent the pin of the f6 knight, is by far the commonest move here.]
8.a3 Ba7 9.b4 Be6 [Yasser Seirawan, in his video commentary on the Internet Chess Club, thought 9...Bf5 was a useful alternative, with a view to getting in e5-e4 for Black and, if 10.e4 to prevent it, then 10...Bg4 and Black will have a good home for his c6 knight on d4.]
10.Nd2 Rb8 [Yasser Seirawan preferred the more direct 10...d5 here, but the choice is not critical. This line of the English is quiet and strategic, contrasting with the ultra-sharp Short-McShane game going on alongside.]
11.Rb1 Ne7 12.a4 Qd7 13.b5 Bh3 14.Ba3 h6 15.e3 Bxg2 16.Kxg2
16...Bc5 [Very committal, but still not really classifiable as an error. 16...axb5 17.axb5 Bc5 would ensure that the resultant doubled pawn on c5 could be defended by the move b7-b6.]
17.Bxc5 dxc5 18.Nf3 Qe6 Black threatens to undermine White's pawns with e5-e4 so Magnus decides he has to stop that happening with...
19.e4 c6 20.Qb3 Rbd8 [Superficially, 20...cxb5 looks attractive, to undouble the pawns, but 21.cxb5 Qxb3 22.Rxb3 Ng6 23.Rc1 would leave Black's queenside pawns a little vulnerable to White's rooks. A player of Magnus's stratospheric ability would be quite capable of capitalising on such a small edge in the long run.]
21.bxa6 bxa6 22.Qc2 Black's c5 pawn is now a long-term weakness but White's backward d3 pawn is a compensatory factor from Black's point of view.
22...Ng6 With the immediate threat of ...Nf4+! but White can easily stop this.
23.Ng1 In a sharp, tactical struggle this sort of retreat would be costly in terms of time but in this quiet, manoeuvring game it does not count as a concession.
23...Rb8 24.a5 Nd7 25.Na4 Qd6 26.Ne2 Qc7 27.Qc3 White has to defend a second pawn weakness.
27...Rfd8 28.Rxb8 Rxb8 29.f4
29...exf4!? [Yasser Seirawan considered this the critical point of the whole game. He thought the text move was an error of judgement, preferring the idea 29...Rb7!? with the idea of Qb8 and an invasion along the b-file. But some analysis engines favour Adams's plan.]
30.gxf4 Qd6 31.Kh1 Rb4 32.Qc2 Nh4 [Another turning point. Black could try 32...Qc7 here, with the simple threat of taking the a5 pawn, but perhaps he was afraid of a white kingside attack should he concentrate his major pieces on the queen's flank.]
33.Nac3 Qg6 34.Ng3
34...Nf6? [Perhaps this is the true turning point of the game. The text move allows White to play e4-e5 with tempo and establish a knight on e4. But it looks better to leave the knight where it is, defending the c-pawn, and play 34...Qe6! instead. Black seems quite handily placed then, with useful replies to pawn pushes, e.g. 35.f5? Qd6! when White's progress stymied and Black is significantly better.]
35.e5 Nh5?! [Black could admit his previous mistake and play 35...Nd7 when he is not worse.]
36.Nxh5 Qxh5 37.Ne4 Kh8? [This is probably the fatal error. Black needs to play 37...Qf5 when 38.Qf2 Qh3 39.Re1 Rb3! seems to hold things together, e.g. 40.Nxc5 Rb2! 41.Qxb2 Qf3+ 42.Kg1 Qg4+ 43.Kf1 Qh3+ with perpetual check.]
38.Qf2 Nf5 39.Nxc5 [Not 39.Qxc5?? Qh3! and White suddenly has insoluble problems.]
39...Qh3 40.Re1 Nh4 This makes things relatively easy for White but Black was probably losing anyway.
41.Qg3 Qxg3 42.hxg3 Nf3 43.Rf1 [Black's forlorn hope is 43.Ra1?? Rb2! - a sneaky mating configuration beloved of all competition chessplayers.]
43...Nd4 44.Kg2 Magnus's king is on its way to e4 where it will be safe and ready to support pawn advances.
44...Ne6 45.Nxa6 Ra4 46.f5 Ng5 [There is no time for 46...Rxa5 because of 47.fxe6 Rxa6 48.exf7 and the pawn queens.]
47.Nc7 Kg8 [Black would like to play 47...Rxa5 but 48.e6! fxe6 49.fxe6 Re5 50.d4! and White will soon have two united passed pawns on their way to promotion.]
48.a6 Kf8 49.Kf2 [49.Kf2 Ke7 50.Rb1 Kd7 51.Rb7 Kc8 52.e6 soon decides.] 1-0