The Colombian even pledged he would banish his own self-doubt after a slow start to the season.
In a brief post on his official Instagram account, Morelos wrote in Spanish: "I will go against everyone who thinks I am not going to make it, even against myself if one day I doubt it."
Morelos has only scored once in six appearances after coming back from the thigh injury which ruled him out of the latter stages of last season.
The 26-year-old had his fitness and attitude questioned by manager Giovanni van Bronckhorst after being left out of the squad for Rangers' Champions League play-off second leg against PSV Eindhoven and remained on the sidelines for several more matches.
He was restored to the starting line-up for last week's Champions League clash with Napoli at Ibrox and played 72 minutes but was left on the bench for the duration of Rangers' cinch Premiership game against Dundee United on Saturday.
The former HJK Helsinki player's replacement, Antonio Colak, scored both goals in a 2-1 victory to take his tally for the season to nine.
Morelos will have the opportunity to work on his fitness over the international break after being left out of the Colombia squad for friendlies against Guatemala and Mexico.