Holding the Black b5-pawn will turn out to be critical, though I did not foresee it at this point.

The broad strategy for the rest of the game is now set: Black is threatening to mate the White king on the back rank (or squash him against the Black king-side pawns if he flees forwards); White must try to force perpetual check. For the next 15 moves, the White queen and the Black king play cat and mouse. Where will the Black king find refuge?

If 45. Qd7+ then the Black king dives towards e2 and either d1 or f1 and finds a safe haven on the back rank.

At last the White queen has run out of checks; the Black king has found refuge on f4 of all places. Note that the Black pawns are holding the crucial squares a4 and d4, protecting the king from checks.

If instead 49. Qa8 or Qg7, Rxg2+; 50. QxRg2, RxQg2+; 51. KxRg2, Ke3 etc. and Black promotes a pawn before White's h-pawn promotes.

White played quite well, given the ratings differential and the problematic endgame. 0-1