1. d2d4  1... g8f6  2. c2c4  2... e7e6  3. b1c3  3... f8b4  4. d1c2  4... e8g8  5. a2a3  5... b4c3  6. c2c3  6... d7d5  7. c1g5  7... h7h6 7...dxc3 and 7...c5 are popular alternatives. 8. g5f6  8... d8f6  9. g1f3  9... d5c4  10. c3c4  10... b8c6  11. c4c3 This move is necessary to fight the e6-e5 advance. All this is still theory. 11... f8e8  12. a1d1  12... e6e5  13. d4d5  13... c6b8  14. e2e3  14... c8f5 The computer's favorite move. Caruana, as always, shows impeccable preparation. 15. f1e2  15... b8d7  16. e1g1  16... a8c8  17. a3a4 A new and somewhat strange move. Niemann  spent some time here, so I believe this was not preparation. 17... c7c6  18. d5d6 A brave move. The d6-pawn is passed, but it can also become a weakness. 18... c8d8  19. a4a5 White's idea pops up. The pawn heads for a6, breaking Black's structure. 19... f5g4  20. h2h3 This move leads to problems. 20... g4f3  21. g2f3 A sad necessity. The endgame is much better for Black after 21.Bxf3. 21... d7f8  22. c3b4  22... d8d7 Now Caruana has a much better position. 23. d1d2  23... f8g6 Here and in the next moves, it would be better to play a7-a6 and avoid White's counterplay on the queenside. 24. f1d1  24... g6h4  25. b4g4  25... e8e6  26. g1f1  26... h4f5  27. a5a6  27... b7a6  28. e2a6  28... d7d6  29. d2d6  29... f5d6  30. a6d3  30... g7g6  31. h3h4  31... h6h5  32. g4g3  32... g8g7 Black has a solid extra pawn, and White's queen is misplaced. The position is winning, but we still have some adventures. 33. e3e4  33... f6e7  34. g3g5  34... e7b7  35. g5c1  35... b7b4  36. c1d2  36... b4d2  37. d1d2  37... g7f6  38. b2b4  38... g6g5 now the win becomes problematic. 39. d2a2 White finally gets some counterplay. 39... d6c8  40. d3a6  40... c8d6  41. a6e2  41... d6c8  42. f3f4 Niemann surprisingly decides not to repeat moves. 42... g5h4  43. e2h5  43... c8d6  44. a2a7  44... e5f4  45. f2f3  45... e6e5  46. h5g4 