Muslic was brought in as assistant coach to Dominik Thalhammer at Cercle Brugge in 2021, and was promoted to the main first-team coaching role the following year, replacing Thalhammer in the hot seat on 19 September 2022.[2]
Helped by the goals of Japan international Ayase Ueda, Muslic steered Cercle from the relegation zone to a regular-season finishing position of eighth for the 2022–23 campaign, qualifying them for a streamlined version of the Belgian Pro League's European play-offs. They finished runners-up to Gent in these play-offs for the final European qualifying place, seeing them officially finish in sixth position.
With Ueda moving to Feyenoord, and Kevin Denkey promoted to become Muslic's first-choice striker, Cercle would qualify for the title play-offs for the first time,[3] going on to finish fourth for the 2023–24 season, their highest finish since 2008, qualifying them for Europe for the first time in 14 years, and only the fourth time ever.[4]
Early season struggles for the 2024–25 season did not clear, and after a 2–0 lead over bottom side Beerschot turned into a 2–3 defeat, Muslic was dismissed as Cercle coach on 2 December 2024.[5]