1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1c4  3... g8f6  4. d2d3  4... f8e7 Caruana played this line before in the tournament, against Dominguez, when he saved a lost position. 5. e1g1  5... e8g8  6. b1c3  6... d7d6  7. a2a4  7... c8g4  8. h2h3  8... g4h5  9. c1e3  9... c6d4  10. e3d4  10... e5d4  11. c3d5  11... f6d5  12. c4d5  12... c7c6  13. d5b3 White now is threatening 14.g4 followed by the capture of the d-pawn. 13... h5f3  14. d1f3  14... g7g6 A new move. This type of position resembles some variations of the Ruy Lopez, where there is a battle in the middlegame with opposite colored bishops. White's position is a little more comfortable as his bishop is more active, and his plan is clearer (to advance the pawns on the kingside). However, as Caruana is the best-prepared player in the world and the move 7...Bg4 practically forces this position, he must have studied it very deeply with computers and come to the conclusion that it's not dangerous. 15. f3g4 A logical idea, preparing to advance the f-pawn. 15... g8g7  16. f2f4  16... d8c7  17. a1e1  17... a8e8  18. g4f3  18... c7d7 White's play has been very logical so far, and now he must choose a course of action. 19. e1e2  19... e7d8  20. g1h1  20... d6d5 [%c_effect d5;square;d5;type;GreatFind;persistent;true] Another version of the pawn sacrifice. 21. e4d5  21... e8e2  22. f3e2  22... f8e8  23. d5c6  23... b7c6 Black has excellent compensation for the pawn.