Republic of Ireland international Shane Long hopes that Lukaku can return to the Hawthorns for a second season on loan as part of his development into the complete striker.
He said: "Rom is still young. You look at him and I can't believe he is 19-20.
"He has a lot of learning to do but he wants to learn, is relishing the challenge here and it is good to play alongside him.
"He is a nuisance up front, he is a big strong lad.
"They've got plenty of options at Chelsea and I think he likes it here. He likes playing for the manager. He likes the lads, he finds it fun coming to training every day and he seems happy here.
"Hopefully we can get him back next season and keep him going the way he is going."
Two goal hero Lukaku has set his sights on becoming "the complete striker" and helping West Brom to qualify for Europe.
Lukaku, who is on loan from Chelsea, gave another demonstration of the potential in the 2-1 home win over Sunderland which persuaded the Blues to pay £18 million for his services two years ago.
He scored the opening goal from the penalty spot and his sheer perseverance enabled him to charge down Black Cats keeper Simon Mignolet's clearance for his second - and 12th of the campaign.
The 19-year-old's contribution helped push the Baggies back up to seventh spot in the Barclays Premier League and just two points behind Everton in the race for a Europa League spot.
Lukaku said: "I want to end this season in a European spot and I know we have the players at West Brom to achieve that goal.
"We have the staff, the experience and the up and coming players to do it.
"We've got experienced players back now to push on in the remainder of the season."
"I have personal ambitions I want to reach. I want to score goals but also win as much as possible. If I do better and help the team, that's perfect.
"I work on all different aspects of my game and have the qualities to become the complete striker.
"I have the people around me and players around me to help me improve. Every year, every season is an opportunity to get better."