Lyon, who had already qualified for the next phase, finish second behind Fiorentina, who snatched a late 2-1 win over Liverpool at Anfield. Third-placed Liverpool continue in the Europa League while Hungarian champions Debrecen finished last with six defeats in as many games.
Striker Bafetimbi Gomis opened the scoring on 25 minutes, following up after Debrecen keeper Djordje Pantic failed to block an effort by Sidney Govou.
"We owed this to our fans," Cissokho told reporters after Lyon scored their first win at their Gerland stadium since a 2-1 Ligue 1 victory over Toulouse in September.
"Of course we would have preferred to win the group because playing the (last 16) return leg at home is an advantage, but never mind,"
Lloris and Coulibaly both finished the game with bandages after sustaining face cuts in a clash of heads. The Lyon keeper's injury looked superficial, however, and he should be fit to face champions Girondins Bordeaux in Ligue 1 on Sunday.
"This is just what we needed to boost our confidence before facing Bordeaux," Cissokho said.
