The Latics face Tottenham today with Defoe's five-goal haul earlier this season still fresh in Martinez's mind.
He said: “When you have Jermain Defoe on top of his game he is one of the best goal scorers in world football. You look at his arrogance and that is a great thing for him. He can get into positions and miss three chances, but the fourth is going to go in.
“He has that natural streak of knowing how to score goals and that is unique.
“He is important for Spurs at the moment, and he is going to be vital for England in the summer.
“He is a difficult type to find. If you look in world football, that type of goalscorer is really rare.”