Negotiating an offer, is it too late? after 4 years as a machine operator

I want to negotiate but I am afraid they will withdraw. I have read a lot of threads here and could not find my exact situation. I have a competing interview next week.

Most employers expect a short conversation. Mine did not even blink.

I thanked them and said I was excited but hoped we could talk about the pay. They came back with a bit more.