Tottenham striker Jermain Defoe feels Wayne Rooney must always play on the edge to be at his best.

The Manchester United star is known for his short fuse.

And Defoe said: "People say top players, or ­talented people, always seem to be a little crazy.

"But if you look at life in ­general, people who have got that gift are a little bit crazy and they live on the edge for some reason.

"It's important for Wayne to have that fire. I think you need that fire to achieve anything."