1. d2d4  1... g8f6  2. g1f3  2... d7d5  3. c2c4  3... e7e6  4. b1c3  4... c7c5  5. e2e3  5... b8c6  6. c4d5  6... e6d5  7. f1b5  7... c5d4  8. f3d4  8... c8d7  9. e1g1  9... f8d6  10. d4f3  10... d7e6  11. b2b3  11... a7a6 Caruana probably didn't expect this move, since he had to take some time to think after seeing it. 12. b5d3  12... c6e5 All this was played fast by Nepomniachtchi. He must have studied this line during his world championship match preparation. 13. f3e5  13... d6e5  14. c1b2  14... a8c8  15. a1c1  15... e8g8  16. f2f4 If we consider that 16.h3 leads to a known position, then this is the first new move of the game. It's reasonable to assume that both players were out of book at this point. 16... e5c7 Black has many decent options. 17. c3e2 