One of the most important reason why Cristiano Ronaldo is where he is, its because of hard work. But let us just say that an open mind to fashion only gave him better avenues! The trademark Ronaldo side style is the experiments that he did with his sides.
Always combining his cool looks with undercut, this guy then altered the basic idea of an undercut all together. The uniqueness that you can bring into your own hairstyle with a hint of risk is what alters the game entirely. He is popularly known as the hairstyle icon because of the dash of risqué styles he experimented with.
You will always find an edginess in his look and that was always focused around the sides. One important reason is that footballers are shot from all angles and more so from sides because they are on the field running. This is his good angle. Also, he knows he has a sexy side profile making his style even more irresistible.
That being said, some of the basic styles that might inspire you is an undercut with some simple razor action, funky side burns, interesting parting are all elements of a cool new look and everyone can surely give it a short even if so in a small magnitude!