Everton manager Roberto Martinez has praised Romelu Lukaku, insisting that the striker's purchase was "money well spent" and believing that he could become "the best striker in the world".

The Belgian, who cost the Toffees £28m from Chelsea in the summer, struck his side's first goal in their 2-1 win over West Ham United on Saturday, before setting up Leon Osman's winner in the second half.

Martinez is quoted by the Mirror as saying: "Whatever money we spent, it was well spent. Remember the assessment of Romelu is what he brings to the side. No one else in our squad can give us what he gives.

"He holds the ball, brings a lot of fear to the opposition, as he always gets players around him and opens the spaces at all times. I think it's what he means for the squad, and you don't get that sort of player easily.

"I think he's doing exactly what the team needs. He's such a winner he wants to become the best striker in the world and has the ­potential to do that."

Lukaku is Everton's top scorer so far with five goals in 11 league starts.