The Brazilian legend tweeted this week he would be watching Flanagan on recommendation from Reds fans.
Flanagan said: "To see a tweet from Cafu, someone I've looked up to, a brilliant right-back all of his life for Brazil, AC Milan and others - for him to comment on me is amazing really.
"You think: Is it real and did he really tweet that? It's a great boost for me. Some fans call me stuff, some fans call me other stuff! But for him to notice me and say he's going to watch me is just brilliant.
"He's a legend in the game, so hopefully I can keep improving and maybe one day reach the top like he did."