Speed has always been a big believer in the talent of the Cardiff boy.
He said: "I think everyone was surprised last year when he burst on to the scene but I wasn't because Id seen him play for Wales previously but no one takes much notice of Wales.
"It wasn't a surprise to see him play like that against Inter. He's a fantastic player. Can he be one of the best wingers in Europe? He already is.
"He has the ability to be there for a long time. Gareth is similar to Ryan Giggs in the way he burst on to the scene."