Roberto Martínez believes Romelu Lukaku's decision to join Everton has been vindicated by the extra playing time that has allowed the Belgium international to develop into "a proper man".

The 20-year-old has scored four goals in four appearances for Everton since arriving on loan from Chelsea on transfer deadline day. Martínez has made Lukaku his first-choice striker in recent weeks, an experience he was unlikely to receive at Stamford Bridge, and claims the added responsibility has allowed the striker to flourish.

"Romelu can be as good as he wants to be," the Everton manager said. "He will get the opportunity here. He will have the time to experiment things and try things. Remember that he hasn't played many 90 minutes in his career and it is important he does play 90 minutes for us because that allows his game to go into full flow. That is the way he is as a player.

"How many games did he play 90 minutes at West Brom? He was involved in 35 games – how many did he play in [from the start]? Seven.

"So it is like seeing a young man who has now become a proper man with an important role and that's what we want him to have here. This is the first time in his career that he is going to take that role so everything is in his hands."