James Toney and Mayweather are both counter-punchers, and they have both beat up a lot of guys that thought that pressure was the answer. Ask Iran Barkley. And what if the counter puncher is the one applying the pressure, trying to make you throw a punch he can work off, like Duran or LaMotta or Basilio?
There are counters to every punch, and a guy that is real good at being a counter puncher isn't going to be sitting there looking to counter off every punch you throw (unless you are throwing them just to be punching and giving up free shots). Rather, he'll be looking to get you to throw a particular punch so he can throw a particular counter, like Toney did with right hands. So how do you beat them?
Maybe you can draw them out of their spot, in the case of a Toney or Mayweather type, get them to come to you. How you do that, I don't know. Figure out what punch they are trying to set up a counter off of, and then don't throw it, make them come up with a new plan and maybe make a mistake. Or throw the punch and counter their counter.
But any fighter that is any good is a counter puncher, even if he is aggressive, because it is easier and more effective to hit a guy as he is trying to hit you.