The 18-year-old had been out of action since last November due to a serious knee injury but was named on the bench for the clash with Levante.
The Spain international was introduced in the 81st minute of the contest, replacing Luuk de Jong, and he found the back of the net with a long-range effort in second-half stoppage time to cap a strong performance from the home side.
"I did not imagine a return like this. Here you always have to win. I am happy for the victory, we have a lot left. I thank the doctors and physios who have been with me. Also to the fans," Fati told Movistar after the match.
"I have thought about helping the team. I have also thought about my family, who have suffered these months. Also for the people of the club. They have been a great support for me in all these months. I am one more. I will try to add what I can. I will try to help the coach and be available to help.
"It will depend on how I find myself. I will have to earn the minutes. This is very long, it has just begun. We are Barca and we have to fight for everything.
"For me the number 10 is not a source of pressure, it is a source of pride. I thank the club and the captains for giving me the opportunity to wear it. It is not pressure, but gratitude. We are going to fight for La Liga, for the Champions League and for everything. We have to fight and work for that."
Fati has now scored 14 goals and registered five assists in 44 first-team appearances for Barcelona. body check tags ::