The Belgium international has scored 15 goals in the Premier League this campaign for Paul Lambert's side since his move from Genk last August.
Phillips told the club's official website: "For me he will go on to be one of the top Premier League players. He has got everything. He is strong, powerful, skilful, he can score goals.
"He needs to step up once again to the plate these next few games. You have to give him credit, without a shadow of a doubt. He's just got on with his job.
"The pressure that has been on him has been immense but he's responded. That tells me he can take the pressure on his shoulders. The goals he has scored have been excellent at important times."