on 12 january 2018, hajdin agreed on a three-year deal with red star belgrade. the transfer fee was reported as €200k plus 20 percent of the future transfer. he officially promoted in new club by sporting director mitar mrkela next day. hajdin chose to wear number 34 jersey. hajdin made his official debut for the club in the serbian cup match against mačva šabac on 14 march 2018. hajdin also made his league debut for the club on 13 may 2018, replacing milan rodić in 52 minute of the away match against vojvodina. after passing the complete pre-season with first team in summer 2018, hajdin was excluded from the uefa champions league player list for the 2018–19 qualifying phase.