The pair played together at AS Monaco.
"The normal choice is (Kylian) Mbappe," Silva told L'Equipe. "In coming years, he can become one of the best in the world.
"But I can't decide between him and Fabinho.
"Fabinho still has 10 years ahead of him and I really enjoyed playing with him. He's very intelligent, he's a very good person and a fantastic player."