West Brom striker Lukaku: Mulumbu has goals in him
The DR Congo international took the man of the match honours in Saturday's 2-1 win over in-form Swansea.
"I think Youssouf was the best player on the pitch on Saturday and he seemed to start every attack," on-loan Chelsea striker Lukaku told the WBA website.
"His role has changed slightly and he seems to push up the team more. All he is missing is some goals and I keep telling him that in training.
"He is working very hard on his finishing and his offensive play. It's hard when you've been playing as a holding midfielder and now you have moved up the pitch into a more attacking position.
"It's very difficult in the beginning but he will get there and by the end of the season he will score a few goals to help us climb the league."