In June 2015 at the inaugural 2015 European Games in Baku, Chupkov won four gold medals, in 200 m breaststroke, 100 m breaststroke, 4 × 100 m medley (with Daniil Pakhomov, Vladislav Kozlov and Filipp Shopin touching in 3:36.38), a new junior world record breaking the previous record held by Russia in 3:38.02 at the 2014 Youth Olympics. and 4 × 100 m mixed medley (with Daniil Pakhomov, Arina Openysheva and Maria Kameneva at a time of 3:49.53). Chupkov broke two junior world records including shattering a previous record held by himself set at the 2014 Youth Olympics. He was chosen as the flag bearer representing the Russian Federation at the closing ceremony of the Games.