There were fears Kompany would not be available for the competition after he suffered an injury in the 0-0 draw against Portugal on Saturday.
TALKING POINT - How serious is Vincent Kompany's injury?
Dedryck Boyata has been included in Belgium's 23-man squad for this summer's World Cup finals in Russian Federation.
Kompany walked off the pitch without waiting to be substituted early in the second half after he overstretched in a challenge on Gelson Martins.
"You could feel that when he came off we were all very much anxious", Martinez said. He's not a young player, he knows his body.
The Portugal superstar posted a picture of himself alongside his close friend Miguel Paixao on Instagram while they together stood at a clay tennis court.
The three-times Premier League victor has suffered from frequent injuries throughout his career and missed out on Euro 2016, although had been playing for his club since the start of this year.
Santos expressed satisfaction after the match, saying his team had done well to keep a clean sheet against a team that set a joint record of goals in qualifying for the World Cup.
Belgium began with their strongest possible 11, apart from the injured Axel Witsel and Thomas Vermaelen, and a trial three-man defence.
"Losing Vincent would be bad news", said Hazard.