The 19-year-old Spanish winger, who is at Goodison Park from Barcelona on a season-long loan deal, has made four appearances for the Toffees this term.
"There's a big gap in terms of physicality between the English and Spanish leagues - it's a lot quicker here and there is a lot more contact, so for players who are artists with the ball like Gerard there will always be a period of adaptation," Sky Sports News quotes Martinez as saying.
"Gerard is doing that very well. He is making the difference when he is on the pitch. He is learning bit by bit, he is very quick and I am sure that in the next few months Gerard will play a very big part in this team."
Deulofeu featured for Everton on Tuesday night in their third-round defeat to Fulham in the Capital One Cup.