Firmino told FIFA.com: "He's phenomenal.
"You simply can't say that he's not a magician. He has magical powers. He produces plays that don't exist, that you couldn't make up.
"You always have to watch replays of his plays to understand what he's done. He's an unbelievable player. It was a pleasure to play with him at Liverpool, and it's a pleasure to play with him for the Selecao.
"I'm a huge fan of his. He's one of the very best players in the world."