Kompany, meanwhile, has not featured at the World Cup so far due to a groin injury.
"Romelu Lukaku is fine, he's fully fit. He completed the training session today (Friday) so he's got no problems. He should be available," Martinez told reporters in his pre-match press conference.
"Thomas Vermaelen had a nasty knock in his eye, looked like a boxer this morning so I think he forgot about all his previous problems. Apart from his eye - his vision is not perfect at the moment because of the inflammation - he'll be fine and will be perfect to train tomorrow.
"Vincent Kompany reacted very well to his 20 minutes – that was always the plan. He is now fully fit and available for selection.
"We had to rely on our medical department to make big calls on players who weren't fit for the start of the World Cup."
Belgium set up the meeting with Japan after topping Group G in the final standings.