Martinez and Lukaku worked together during their time at Everton and the Manchester United forward is an early contender for the Golden Boot, but his international boss is adamant that his focus is purely on the team.
"He's not here to be the top scorer at the World Cup, he's here to help the team to win and do his role," Martinez told reporters.
"His role is of someone who can score goals. I know Rom well, I spent the biggest amount in Everton's history on a player because of the quality of his finishing, not because he was a player that could contribute things other than scoring goals.
"His role in the national team has become that. Maybe before there was confusion, when you ask players to do things they can't do it becomes confusing. I think Rom now knows his role. I wouldn't expect any player to work towards an individual reward, the players know what they have to do to make a winning team."
Belgium will play Tunisia on Saturday in their second fixture of the group stages.