And I was there 1

I'm starting to believe thet the best games are these where one of the players chooses to resign, they are a nice mental challenge. Anyway, everytime I have the time, I love high rated (higher than mine) 10 minutes games because there are not so many blunders and I get to see what others think. I took the liberty of pasting this game between two people I don't know. the game is awkward because, from my point of view, white suicides in the opening by getting its light square bishop blocked, but then a nice middle game blunder from black comes in play and could have changed the game:

I stopped my comments because I'd like you to look for the nice mistake black did and the very next move white didn't do.

Move 26 from black makes it win an advantage, but they didn't know how to use it afterwards: