1. g1f3  1... g8f6  2. c2c4  2... e7e6  3. d2d4  3... d7d5  4. b1c3 The players reached a popular Queen's Gambit tabiya by a less common move order. The Mongolian first board opts for the Ragozin Defense out of many reasonable possibilities. 4... f8b4  5. c1g5  5... h7h6  6. g5h4 A clever choice by Carlsen. It was safe to assume that his young opponent was booked up in the main lines after 6.Bxf6 Qxf6, so the Norwegian deviates early. With this move, he tries to steer the game into less explored territories. 6... e8g8 Judging by the time spent on this move, it seems Batsuren was surprised by the world champion's move and decided to play it safe instead of going for the critical continuation. 7. e2e3  7... b8d7 Black continues developing in a relatively passive fashion. 8. c4d5 This is a good moment to make this exchange for two reasons: (1) White doesn't want to lose a tempo developing his light-squared bishop to d3, so he eliminates the dxc4 possibility. (2) Having put his knight on d7, Black has blunted the c8-h3 diagonal for his light-squared bishop, so we don't have to worry about moves like ...Bg4 anymore. 8... e6d5  9. f1d3  9... c7c6 Black is going for the classical QGD setup with the Carlsbad structure, although that means his bishop on b4 is misplaced. 10. e1g1  10... b4d6  11. d1c2  11... f8e8 Interestingly, we have reached a position from the 4.Qc2 Nimzo-Indian Defense by transposition. White wins over 70\% in the Mega database, so it's not something I'd recommend for Black. It is instructive to see how Carlsen increased the advantage in the game. 12. f1e1 With this move, he indicates that the e4-break is in the cards. This idea makes sense considering the pin on the f6-knight. 12... d6e7 It's not a good idea to play so often with the same piece in the opening, but Black can almost get away with it here since the position is relatively closed. Still, he is facing problems with his development. 13. h4g3 A strong prophylactic move that avoids 13...Ne4. 13... d7f8  14. h2h3  14... b7b6 Batsuren's previous play wasn't particularly inspiring, but this is where his real troubles start. This move weakens the c6-pawn, and Carlsen will exploit it to the fullest. 15. e3e4 A move that yells, \"Play me $1\" Carlsen doesn't miss his chance to open the center at the right moment. 15... d5e4 It is difficult to criticize this natural reply, but it's probably already a decisive mistake. 16. c3e4  16... c8b7  17. f3e5 The side with the isolated queen's pawn should strive to attack the king, and this knight sortie is the first step toward this goal. The f7-pawn is an immediate target. 17... f8e6  18. e4f6  18... e7f6  19. d3h7 An essential check that uses the poorly defended f7-pawn to force the black king to move to f8. The point is that it will be much more exposed here than on h8. I'd like to point out that Carlsen carried out a similar attack against GM Granda Zuniga in the Isle of Man, 2017, where Bh7+ $1 was equally instrumental. 19... g8f8  20. a1d1 You have to admire the elegancy with which Carlsen solves minor problems, such as the hanging isolani on d4. Black cannot take it for tactical reasons, meaning he has no real counterplay left. 20... f6e5 This seems like a sad necessity. 21. d4e5 The most natural recapture. White creates a powerful kingside majority with a tempo. 21... d8e7  22. f2f4  22... c6c5 Black was approaching time trouble, so he tried at least to create some semblance of counterplay with ...Nd4. However, it's all too little too late.