In the main-team squad, Lunin made his debut as a start-squad player at the age of 17, in the match against Karpaty Lviv on 16 October 2016 in the Ukrainian Premier League.

However, at the end of the season, due to financial irregularities, Dnipro was relegated directly to the Ukrainian Second League (third level of football), and many players, Lunin included, were allowed to leave the club.

[23] On 8 November 2023, Lunin was called to action in Real Madrid's Champions League group stage match against Braga after Kepa suffered an injury during the warm-up.

[24][25] Lunin made a significant contribution to the team's performance by saving a penalty shot from Braga winger Álvaro Djaló in the fourth minute of the game, which helped maintain Real Madrid's lead in their group standings.

[28] Ancelotti hailed it as Lunin's "best game" for the club, emphasising the goalkeeper's critical role in securing a strong position for Real Madrid to advance in the competition.

[38] At the age of 19 years and 40 days, he became the youngest debutant in the national team during that time, surpassing the previous records set by Maksym Koval and Oleksandr Shovkovskyi.