I love the way Hearns set up Duran like that. Now for the thread starter, the best counters are relative depending on the punch you are evading or blocking to take advantage of the opening. For example, if you're able to see and time the right cross coming from an orthodox stance you could slide your upper body to your left (with your guard up) and counter with a left hook to the body or face>(harder to land than the body shot) and follow it with your own right cross or another left hook. It really depends on what punch, how open the fighter leaves himself and your ability to time his shots and land yours.