[1] He played 36 games in the regular season, and then participated in the team's deep run to the playoff finals, where they were ultimately defeated by HKM Zvolen.
Submitting his name for consideration in the 2021 CHL Import Draft, Mešár was selected ninth overall by the Kitchener Rangers of the Ontario Hockey League (OHL).
[5][6][7][8] On 7 July 2022, the Montreal Canadiens selected Mešár 26th overall (using a pick previously acquired in trade from the Calgary Flames for Tyler Toffoli).
[15] Team general manager Kent Hughes suggested that Mešár's next step was undecided at that particular juncture, offering that he would likely play either at the major junior ranks in the OHL with Kitchener or professionally in the American Hockey League (AHL) with the Canadiens' top affiliate, the Laval Rocket.
[22] After a strong start to his inaugural campaign with the Rocket, Mešár would suffer a lower-body injury after just five games played, sidelining him for a period of eight to ten weeks as a result.
[24] Mešár made his international debut for Slovakia with the country's under-18 national team at the 2021 Hlinka Gretzky Cup, recording two goals and six assists en route to winning a silver medal.