 He made his debut for BATE in the 2014 Belarusian Super Cup final against FC Minsk, and went on to score a goal 20 minutes into the game.On September 29, 2015, Mladenović scored two goals for BATE in the 2015–16 UEFA Champions League Group E against Roma.Thanks to his breakthrough game, Mladenović was listed on UEFA.com's Champions League "Team of the Week" on October 1, 2015.