Liverpool midfielder Allen: Everton's Fellaini a BEAST
Allen's Wales face Fellaini and Belgium tomorrow night.
Allen said: "Fellaini is a beast, he's a man mountain, and not many people will come out on top if they get into a physical battle with him.
"But there are other ways of dealing with him and all the other talent that the Belgians have got.
"We need to focus on how we perform because we want to make Wales a difficult destination for teams to travel to."