One of my online chess games. Two or three weak middle game moves by me and I got hit by an avalanche. Some annotations below . . .
1. …c6 Caro-Kann Defense
3. e5 Advance Variation
3. …c5 Botvinnik-Carls Defense
13. Qd4? Maybe 13. a4, instead of putting the queen where Black can point a bishop at it.
29. Ra2 Black has the best of things at this point. Possibly Rxf8, taking a piece out of the attack, is an improvement.
34. Ra8? Moving the rook back to a2 would have been better.
39. …Ra1 I thought 39. …Ra2 was better but this move still doesn’t put much of a dent in a large Black advantage.
41. Re2?? 41. Ke3 could have prolonged the agony. The game is really over at this point, but in a blitz game where we both had a little under 40 seconds left, why not play it out? Time constraints sometimes lead to unexpected blunders.
41. …Qc1 Not that I computed it at the time but Black has a forced mate from here, although it’s a long sequence.