Tennis players fantasize about drubbing the top-ranked Rafael Nadal . Luke McShane, an English grandmaster, got to live out the chess version of such a dream last week at the London Chess Classic , where he soundly defeatedMagnus Carlsen, the world’s No.1 player, in the first round.

McShane, 26, is on the outskirts of the game ’s elite, ranked No. 100 in the world . But when he was a boy, he was anointed as England’s next great prodigy. He won the under-10 world championship when he was 8 andbecame a grandmaster by 16 — the youngest, at the time , to ever do so inhis homeland.

He has not achieved what has been expected of him. Maybe he was not as talented as some thought. Maybe life, and other interests, got in the way.

He stuck to a more common path by staying in school , eventually enteringOxford University in 2003. After graduating in 2007, he got a job atGoldman Sachs as a trader .

But McShane continued to play chess, and this year he tied for first at theRilton Cup in Sweden and won both the Canadian Open and the Remco Heite tournament in the Netherlands.

None of those results could have predicted what he did to Carlsen.

McShane chose the English Opening , and Carlsen answered with a symmetrical setup that he had used successfully at the Chess Olympiad.

McShane’s 7 d4 and 8 Bh6, voluntarily ceding the bishop pair , were unusual, but gave him an advantage . After 9 Nd4, the best response would have been 9 … Bd7. Carlsen’s 9 … Ne5 was aggressive but not as good.

Carlsen’s problems were apparent after 11 Rfd1, when White threatened 12 c5 and Black’s position was uncomfortable.

Perhaps Carlsen should have tried 13 … Nb6. The game might have continued 14 c5 Nc4 15 Qb3 Nd2 16 Qc2 ab4 17 Nd5 e6 18 Nb6 Ra5 19 Nc8 Rc5 20 Rd2 Rc2 21 Rc2 Qd7 22 Nb6 Qd8. White would then have had only a small edge.

McShane’s 18 Nc6 was a nice move , though Carlsen would have been only a bit worse after 18 … bc6 19 bc6 Qa5 (not 19 … Qc6?, then 20 Nf6!) 20 cd7 Bd7 21 c5 Bg4 22 Rdc1 dc5.

Carlsen blundered with 20 … Qc5; he should have played 20 … e6.

McShane’s 22 Na6 was brilliant. Carlsen could not have escaped by playing 22 … Rf8 because 23 c5 Nc5 24 N4c5 dc5 25 Qc5 e5 26 Qd5 Kh8 27 Nc7 Rb8 28 b6 would have given White the advantage.

McShane played the last part of the game flawlessly, and Carlsen resigned; his bishop would have been no match for McShane’s rook in the endgame.

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In the analysis in last Sunday’s column, Black could not have saved his pawn by playing 6 … Nb6 because White could have won it back after 7 Bc4 Nc4 8 Qa4.