Big players make mistakes too, and then they make up for them. He's a giant, this lad. Might just be the best player at leading by example we've had since Vieira. I know Ode is the de facto captain but I doubt there's a single player in the entire club who'd dare to go against an order from Gabriel.
I was a bit sceptical after his first season but he has grown into the kind of elite centreback you need at the back if you want to win the league. He's in the same tier as guys like Vidic, Ferdinand, van Dijk, Stam, etc. Only ones I've ever seen at Arsenal with a higher ceiling were Sol and Kos.