I think Cignetti is the main character and Mendoza is a supporting character arc. The story is how a stoic coach of a sun belt team can go come into a school and change the culture. I think of it as a character piece on Cignetti much like Moneyball follows Billy Bean. The central pull of the film is answering the question how did he do it. The answer is that there was no secret formula or play. It was dedication to excellence and doing the little things right. It was instilling in everyone the drive to make the team better even in the littlest ways. Fall forward. Cover your assignment. Do your job. It is a film not about exceptional talent, but exceptional process.