How did Gukesh hold a draw against Abdusattorov?

The sixth round of Tata Steel chess at Wijk aan Zee only had one decisive result out of seven games. There was very nearly a second, as Nodirbek Abdusattorov had a winning endgame against Gukesh D, but the World Champion escaped narrowly.

White had been somewhat better all game, and at move 45, they found themselves in the following position, where White has an extra pawn in a rook(s) and knight endgame. (See the full game on Lichess.)

The engine did not approve of Gukesh’s 45. …Kf8?, suggesting instead 45. …Rb3! to sidestep the knight fork on d3 while attacking f3. Then Kg2 Kf8 Rxf7+ Ke8 would carry the threat of …Rxe5 for Black, eliminating the defender of the white rook. There are tiny differences about eight moves down the road, where in the following position (from the game), the black rook would be on b3 instead of c3, leaving the knight much more free to move, and Black would be holding:

Abdusattorov’s last winning chance came on move 59, where he had to play h6! Rg8 Rc7!, pinning the knight again, and that was not even the end of the subtleties.

After Re8? Ne6 h6 Re5! Black gets tactical threats of their own (namely, Nf4+), so White allowed a perpetual check by …Rc2-Rc1 and took the draw. This is another great example about how a machine evaluation does not take into account the difficulty of finding the best moves, especially against an opponent who is eminently capable of making your decisions as tough as possible. White did everything right, except for one move!