I checked the game with the program Komodo 9.42 64 bits.

<3...cxd4> earlier that same year, Carlsen had played 3...Nf6 here, transposing back in regular lines later (see Richard Flores vs Carlsen, 2001)

<5...a6> In the mentioned game (Richard Flores vs Carlsen, 2001), Carlsen had played 5...g6 here, which had resulted in a victory.

<7.Bxf6?! Qxf6!> As SteveToyne wrote above, the most popular move here is 7.f4. I prefer Tennyson's comment, though: <Tennyson: 7.Bxf6 is played to simplify the position, but black gets full equality immediately.>

<9.Nf3N> This was apparently new at the time this game was played. 9.Nxc6 bxc6 10.0-0 Be7 = Egbert Clevers vs. Martin Vinck, Limburg Open Under 18 (Netherland) 2000, round 4, 0-1.

<12.Nd1> Not really a mistake, but 12.Rad1 was to be preferred.

<14.Nxe5?!> Dubious. 14.Qe3

<17...Qxd5> Forcing the trade of the queens. More precise was 17...Bc5+ 18.Kh1 Qxd5 19.Qxd5 Bxd5!

<22.bxa5?! Rxa5 / >

<23...Raxa2?! 24.Rxa2 Rxa2> Carlsen already had a winning advantage (or very close) according to the computer. 23...Bd6! and now what? A) 24.h3 g6! ;
B) 24.Nf2 f5! ;
C) 24.f5 exf5 25.Rxf5 Bxh2

<25.Rf2> 25.f5! ...

A) 25...Bc5 26.Rd3! exd5! 27.Rd5 Bb6! 28.Rxb5! (or 28.Rxf5 Rd2! 29.Ke1 Rxg2 30.Rxb5 Bc7! (beware of the backrank mate!) 31.Rc5! Bd6! 32.Rx8+! Bf8 33.h3 ) Bc7! 29.Rc5! Ra7! 30.h3 g6

B) 25...Ra6 26.fxe6 Rxe6

<25...Ra4?!> 25...Ra1! 26.Ke1! (if 26.Rd2 g5! 27.fxg5 Bxg5 28.Rd4 / ) b4! 27.csb4! Bxb4+ 28.Ke2 Now Clements is preparing for a long siege...

<32...Kg7> Better is 32...g5!

<33.Nc5> 33.h4!

<34.Ne4> Again: 34.h4!

<39.Kg2> This was the only playable move. For instance, if 39.Re3?? Rxe3+! 40.Rxe3 Bc5+! 41.Kf3 Bxf2 42.Kxf2 Kg6 with an easy win.

<40.Nh3> Better is 40.Rd2 still holding.

<40...Rd3> 40...Bd6! /

<41.fxg5+?! hxg5 > Now, Carlsen is winning. White had to wait here. 41.Nf2! .

<42.Nxg5!?> Clements is sacrificing his knight for 2 black pawns, betting that the last black pawn won't be able to cross to queen and that the boy won't know how to materialize a win. An interesting bet!

<44.Re2? Kg4!> A serious mistake here. Clements lets Carlsen's king get closer to the white fortress without any hampering... 44.Ra6 or 44.Rb6 were better.

<47...Kg5> Only move. If, for example, 47...Kh5?? 48.Rxd2 Bxd2 49.g4+ fxg4 50.hxg4+ and without any pawn left, Black cannot win!

<59...f4> Only move. Of course, the disappearance of Black's last pawn would dissipate any winning chance!