Obviously a penalty. The biggest telltale is Sarabia putting his hands in the air when he makes contact, it's a strikers tackle.
Blaming Buffon for the goal don't understand goalkeeping, that was a fluke shot and impossible to read.
Generally we were pretty shit but I remember going to the same fixture before and it being the same. I thought we looked tired and have for a few weeks, but the standard of play shouldn't be so poor.