The striker scored in victory over Crystal Palace last weekend.
“The one thing he did, that he should have done against Leicester, was score," said Allardyce. “It was a very good header at an important time.
“His hold-up play and his work-rate were good. He has got competition – obviously Cenk's (Tosun) very disappointed that he is not playing – but when somebody up front is doing the job as well as he can and making an impression on the team, then Dominic (Calvert-Lewin) and Cenk have to be a little bit more patient.
"Oumar's goals-per-game ratio is good and he appears, at the moment, to be the best player to score goals for us.
"His contribution on Saturday helped us and, as a team, we now have to keep up that home form. The one thing we need to get better is the away results."