Annotated chess game

At this point I quite like 11.f4 as a way of carrying the fight to the enemy. If Black plays 11.gxf3 e.p. then 12.Qxf3 strikes at once towards f7. If Black is alert this won't save you, but you might just frighten him into making poor decisions...

if you take with the f-pawn, you give your rook play on the f-file, and can try to counter-attack against the weak f7 pawn.

This is where the usual rule of thumb won't do. Usually one would take with the h-pawn here, but circumstances alter cases. Here the f-file is very important to White - so useful in fact that 12.fxg3 claws back much of the advantage lost with the piece. If, say, 12...Qg4 or 12...Qh5, a sudden switch to the Q-side can yield dividends: 13.Qa5! a6? 14.Nc7ch and Black may have to think about the draw. Probably Black's best in response to 12.fxg3 would have been 12...Qd8! 13.Qf3 Rh7 14.Qf5 Rg7 15.Qh3 Rg6 after which it isn't so easy to find a good continuation for white. But bear in mind that Black has to find that wriggle with the rook, as well as the long retreat by the Queen. In an even game, it is a mistake to suppose your opponent will overlook this or that move. When you are down, then what you do is make it as easy as possible for your opponent to make a mistake. That means finding ways of causing as much trouble (on the board of course) as you can. [++++++++++] Incidentally, had the White Queen stood at d1, then 12.fxg3 Qd8 13.Rxf7!! would have yielded an attack good enough to draw, at least.

A good decision: gives Black something to worry about...

It might have been better to take his f6-knight first...

Yes.

After 15.Rfb1 Qh2ch 16.Kf1 Qh1ch 17.Ke2 Qxg2 18.Qxb7 Rb8 19.Qc7 Black's K-side attack stalls, and White Q-side pawns are ready to roll. His pieces more actively placed than Black's, White could really fancy his chances in this line. Of course, Black might be better advised to call off his attack at once, and play something like 15...b6 to keep his Q-side more or less intact.

Sudden death, when really White still had something to play for.