From some other boxing site "Rozier stated, “In my opinion, GGG is an undefeated fighter. I believe and most of the world believe that he won both Canelo fights. He is a tremendous fighter but Sergiy is too and I believe Sergiy will emerge victoriously. His skill set is unique to the middleweight division, he makes very few mistakes that Golovkin can take advantage of and he is much fresher as a professional."
Depends how much GGG has left, if he can still perform like Canelo rematch he’s still got it but beating Canelo is one of the toughest tasks in boxing history. You have to beat Canelo on points for a decision loss, knock him out for a draw and kill him for a win.