DR Congo added to a difficult few days for Nigeria by claiming a 2-0 friendly win in Vise, Belgium.
Sunday Oliseh endured a first defeat as Nigeria coach on Thursday as the Super Eagles went down 2-0 to DR Congo at the Stade de la Cite de l'Oie in Belgium.
Oliseh, who took charge in July, and Nigeria have endured a difficult week following reports of a bust-up in their training camp and the subsequent international retirement of goalkeeper Vincent Enyeama, with first-half goals in Liege proving the difference.
Enyeama arrived at the Super Eagles' training camp having had extra time off following the death of his mother, but turned up to find he had been stripped of the captaincy. Later reports suggested Enyeama had been expelled from the camp.
The Nigerian Football Federation played down the incident as a "misunderstanding which has now been resolved", but in Enyeama's absence, goalkeeper Carl Ikeme conceded after just eight minutes.
Ikeme was beaten low to his left by a Dieumerci Mbokani strike from inside the box and Jordan Nkololo doubled the advantage shortly after the half-hour mark.
Ogenyi Onazi went close with a free-kick for Nigeria before the break and John Obi Mikel tested Parfait Mandanda 25 minutes from time, but there was no way back for Nigeria.
Following a draw and a win against Tanzania and Niger, Oliseh was left to contemplate a first defeat in charge ahead of Sunday's friendly with Cameroon.