1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... g8f6 There are many ways to face the Berlin Defense, probably the most reliable variation for Black, along with the Petroff. It's possible to choose a long-term strategic game with 4.d3 to fight in the endgame like how Kasparov got so much headache in his match with Kramnik or look for a computer line in which your opponent needs to remember many moves to make a draw. Firouzja chooses the last option. 4. e1g1  4... f6e4  5. f1e1  5... e4d6  6. f3e5  6... f8e7  7. b5f1  7... c6e5  8. e1e5  8... e8g8  9. d2d4  9... e7f6  10. e5e1  10... f8e8  11. c1f4  11... e8e1  12. d1e1  12... d6e8  13. b1c3 [%c_effect c3;square;c3;type;Interesting;persistent;true] An interesting pawn sacrifice that is regarded as equal by opening theory with some long forcing lines. 13... f6d4 The best way to refute a sacrifice is by accepting it, as the saying goes. 14. c3d5  14... d7d6  15. f4g5 [%c_effect g5;square;g5;type;GreatFind;persistent;true] 15... f7f6  16. g5h4  16... d4b2  17. a1b1  17... b2e5  18. f2f4  18... c8e6 [%c_effect e6;square;e6;type;Mistake;persistent;true] A new move and I guess a memory lapse, as Black is practically lost after it. 19. f1c4 [%c_effect c4;square;c4;type;GreatFind;persistent;true] 19... e5d4  20. g1h1  20... e6f7  21. e1e4 [%c_effect e4;square;e4;type;GreatFind;persistent;true] This move refutes Black's play. The queen is centralized and keeps an eye on the h7-pawn. 21... d4c5  22. d5e7  22... g8f8  23. e4h7 [%c_effect h7;square;h7;type;GreatFind;persistent;true] 23... f7c4 [%c_effect c4;square;c4;type;Mistake;persistent;true] After this move, there's no hope. 24. b1e1  24... d8e7 Black is forced to give up the queen to prevent mate.