Lukaku has struggled with a toe injury this season and has been out of sorts since his return from the World Cup.
However, Mirallas believes that his teammate will regain the form that convinced Roberto Martinez to make Lukaku a £28m club-record signing from Chelsea this summer.
He told the Liverpool Echo: "He came back after his holiday following the World Cup and it's normal that his first game was difficult against Leicester.
"The second game against Arsenal he played well but he had a problem with his toe and that made it hard for him. He's a big, strong player and when he goes to accelerate he was in pain.
"He's a little bit better now and I think in the next run of games on the horizon he will start scoring and will carry on."
Catch live commentary of Everton's game against West Bromwich Albion here.