At Ghent the visitors were first to score thanks to Joneleit. The match was Frank Vercauteren's debut as Genk trainer.
Maric equalised through a penalty just before half-time. Maric then took the buffaloes into the lead thanks to a free kick.
The result takes Genk to third place in the league.
Earlier in the evening in the West Flemish derby Zulte Waregem beat Cercle Brugge 1 - 0. Zulte Waregem advance to the fifth place in the standings.
Chevalier took Zulte Waregem into the lead shortly before half-time. Cercle's Serebrennikov and Zulte Waregem's D'Haene were both sent off. Later Zulte Waregem's Berrier was also shown a red card.
The depleted field had little impact on the score that remained 1 - 0. Cercle has now won one match out of the last nine.