It's difficult to tell what formation Porto will come out with as theyve played a handful over the past few months. Whatever the case they play with 4 at the back. My guess would be a 4-4-2 but last game I saw it didn't get the best out of one of their best players in pereira but look so much better on the wings. They are going to be physical in the centre so it will be a good to see who we counter that with in the middle. For me it's no rocket science, marchisio must start.