Ossy Martins scored the all important goal in the 13th minute for Rivers United in the match day 18 clash at the Yakubu Gowon Stadium in Port- Harcourt.
The Peoples Elephant remain second in the table despite the defeat and remain on course to secure a play-off spot.
Group A leaders Enugu Rangers ended a run of three games without a win by edging out hard fighting Kwara United 1-0 at the Nnamdi Azikiwe, Enugu.
Felix Ogbuke netted the winner for the Flying Antelopes 10 minutes from time.
