Exciting! 5:23 Anish spend one whole minute in this position, trying to find the sacrifice. Apparently, Nxd4 was theoretically winning after cxd4, Nxh3, gxh3, Bxg4, fxg4, Rf3. Immediately sacking Nxh3 also works, but then white either takes Rxe6 then Nf2, Kg1, Nxg4, fxg4, Bxe6 and the knight on d4 is pinned, or white defends Nh2 then Nf2+ Kg1 Nxd4 cxd4 Bxd4 is also winning for black.