I forgot the example. The one I remember best is this 6FFA where all but me and another much more experienced player(who introduced me to civ in the first place) were irrelevant by the endgame. I was slightly ahead in science and snowballing, and he was playing for culture victory, and succeeding. I could tell that my only option was war. But he has more production. So it had to be nukes, and he had to not know about it, otherwise he could declare war and stop me in time. So I had to make him believe this was not a threat. I did several things like feigning playing for diplo victory(actually to avoid him banning nukes) I got him distracted right there trying to keep me from taking all the cs. By the time I completed the Manhattan Project, his invasion was too late and I was able to nuke his cap and his nr. 2 city. I laid this plan a lot of turns in advance. Afterwards he said he thought the culture win was a sure thing.