[9] He started the 2016–17 Serbian SuperLiga season as the back-up option, having split playing time with Nnaemeka Ajuru for the first half-season.

During the second half-season, Glavčić played mostly matches, pairing with Marko Pantić on two defensive midfield positions.

During the season, Glavčić made 33 matches in both domestic competitions at total, under coach Andrey Chernyshov.

[13] He scored his first goal on 30 October 2019 in a Croatian Cup match against BSK Bijelo Brdo, which Slaven won 2–0.

[17] His great performances in Croatia sparked debates in Serbia about whether Partizan gave up on the player too early.