Everton fans had only seen fleeting glimpses of the winger, who has joined on a season-long loan, with his only appearance in the Premier League a two-minute appearance off the bench.
But on Tuesday, Deulofeu was the stand-out player in Everton's 2-1 Capital One Cup defeat at Fulham, causing havoc with his pace and trickery.
Martinez had previously admitted Deulofeu was frustrated at his lack of game time so far in England, but the Everton manager insists the Spain U21 international will get his chance.
"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," Martinez said.
"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."
Last season Deulofeu scored 18 goals in 33 appearances for Barcelona B, who play in Spain's second tier.