I don't know about best, but there are a couple of MOOCs on coursera titled "Competitive strategy" and "Advanced competitive strategy" by Tobias Kretschmer of L

I don't know about best, but there are a couple of MOOCs on coursera titled "Competitive strategy" and "Advanced competitive strategy" by Tobias Kretschmer of Ludwig-Maximilians-Universität München. They deal with with game theory from a business point of view and are pretty good starting point.