Goals from Fabrice Luamba Ngoma and Jean-Marc Makusu Mundele moves the Democratic Republic of Congo giants top of Group A with one round of fixtures remaining.
The DRC side now sit on 10 points after five matches, two more than their Moroccan counterparts and four more than ASEC Mimosas who eliminated Aduana Stars with victory in Dormaa Ahenkro.
The Black Dolphins raced into a deserved lead five minutes after the interval as Ngoma fired a rasping left-footed shot into the back of the net from outside the area.
Mundele doubled the hosts lead in the 59th minute following a blistering counter-attack. The attacker showed great composure to weave past one defender before guiding the ball past the helpless Raja goalkeeper.
The Green Eagles were unconvincing throughout and although they turned up the pressure on the Vita Club goal in the closing stages, it was too little too late as the hosts claimed all three points.
The Black Dolphins head to Abidjan on matchday six knowing that they have already booked their place in the quarterfinals, but will have to beat ASEC if they are to be guaranteed of holding onto top spot.
Raja are at home to Aduana who will only be playing for pride in Casablanca as the Green Eagles aim to keep their hopes of reaching the last eight alive.
