Kovalenko returned to the national stage after he was selected to the Russian team for the 2019 World Junior Championships in Vancouver, Canada. In Russia's second tournament game, Kovalenko was selected as the player of the game after scoring his first goal and point, notching the game-winner shorthanded, in a 2–1 victory over the Czech Republic on December 28, 2018. He ended the tournament with 3 points in 6 games, helping Russia claim the Bronze medal against Switzerland on January 6, 2019.