This whole “he disrespected me” is bull. It is your boss’s job to motivate you to do better, to be your best.
What was he SUPPOSED to do? Coddle him? Say “oh....would you mind trying to be better, try to be the best you can , so that we can win? If not, it’s ok. I’m not asking you to earn your money or position. Just do whatever you want. I hope I didn’t hurt your sensitive feelings! If I did, I apologize.”