In June 2015, 16-year-old Pakhomov was selected to compete at the inaugural 2015 European Games in Baku, Pakhomov won four gold medals, in (200m, 100 m butterfly), in 4 × 100 m mixed medley (with Anton Chupkov, Arina Openysheva and Maria Kameneva at a time of 3:49.53) and in 4 × 100 m medley (with Anton Chupkov, Vladislav Kozlov and Filipp Shopin touching in at 3:36.38), a new junior world record breaking the previous record held by Russia in 3:38.02 at the 2014 Youth Olympics. Pakhomov also broke a new junior world record in 100m butterfly.