I have an issue at work. I work in an office. A co-worker whom I don't quite like started showing disrespect to me and feeling "superior".

Said coworker was trained to work in the current position by me. He seemed like a quiet pushover type, who didn't know shit about IT (still applies now), despite having a bachelors in Network administration. Took me quite a while to teach him the basics and cost me some nerve cells in the process.

Now the issue is, that after he got past the probational period and got his contract signed (although I strongly suggested our supervisor not to do it), he started to show disrespect towards me and feeling cocky. I have plenty shit and stress on my plate so these instances of him acting out seem like the last straw. Never had an issue with a co-worker like that before.

Can you help me out what would the best course of action be? As much as I want to bash his head in, it's not an option.