in continuing in the mhl in the 2017–18 season, kovalenko's improved strength was evident as he increased his offensive output with loko in scoring 10 goals and 31 points in just 33 games appearing in the mhl all-star game. on february 27, 2018, he was promoted to make his professional debut in the kontinental hockey league as an 18-year old, playing 11 minutes in a 2–0 road victory over spartak moscow. remaining on the roster for the playoffs, kovalenko made his post-season debut in the first-round series victory over torpedo nizhny novgorod, and appeared scoreless in four post-season games before he was returned to the mhl following defeat to ska saint petersburg. kovalenko continued upon his successful season in producing 12 points in 13 playoff games with loko, helping capture the kharlamov cup.