Mohorič, a member of Bahrain Meride, managed to beat Michael Matthews from Australia, who finished second, and Belgian Tim Wellens, who was third.
"I gave my best. It was close at the end, but I was lucky enough to have won," Mohorič said after the race.
Another Slovenian competitor, Jan Polanc, also did very well at the 215-kilometre race between Lacs de l'Eau d'Heure and Geraardsbergen. He finished tenth.