Vincent Kompany shouted at his own fans for throwing a flare at fellow Belgium international Simon Mignolet on Sunday.
The Anderlecht supporters threw the pyrotechnic as the former Liverpool goalkeeper was about to take a goal kick.
Mignolet was shocked and was seen covering his eyes as the flare began to spark in front of him.
Kompany ran over to the home fans in disgust and was seen lecturing them in defence of the Club Brugge keeper.
The former Manchester City captain walked over to Mignolet to console him and asked the fans to support a fellow Belgian.
Anderlecht lost the game 2-1 at home despite taking the lead through Antoine Colassin.
Hans Vanaken grabbed a brace for the visitors including a winner 10 minutes from time. Kompany left City to become a player-manager at Anderlecht but relinquished coaching duties after their worst start to a campaign for 21 years.
The 33-year-old’s side, who are historically the most successful team in the competition, currently sit ninth in the table.
Kompany joined Anderlecht as player-manager in May last year but following poor results, decided to step down managerial duties to focus primarily on being a player.
The former Manchester City captain made 265 appearances for the Citizens in his over a decade sojourn at the Etihad scoring 18 goals.