The U.S. midfielder scored for the third time in his last four games, but nine-man Anderlecht fell to 10-man Zulte-Waregem on a last-minute strike.
Kljestan, who scored for the third time in his last four games, matched his 2012-13 league season total with his third strike. His single-season high in all competitions since joining Anderlecht from Chivas USA is five, set in the 2011-12 campaign.
Thorgan Hazard, who is on loan from Chelsea and is the younger brother of Blues' star Eden, stole the show from that point on with an eventful outing. The 20-year-old Belgium international scored an equalizer, assisted on three other goals -- including Franck Berrier's stoppage-time game-winner -- while also missing a penalty after Anderlecht's Cheikou Kouyate was sent off with a straight red card in the 52nd minute.
Zulte-Waregem was also brought to 10 men when Olafur Skulason saw straight red in the 71st minute, only for Anderlecht to once again fall to a man disadvantage when Olivier Deschacht saw his second yellow for a high elbow in the 90th minute. Hazard's ensuing free kick found Berrier for the decisive goal, which allowed the hosts to leap two points ahead of two-time defending league champion Anderlecht in the Belgian Pro League standings through six games.