The La Masia product has played sparingly this season but came through with the decisive strike against Real Sociedad on Wednesday.
Puig helped his side advance to the Supercopa de Espana final after a 1-1 draw over 120 minutes. The 21-year-old scored from the spot to clinch a 3-2 victory on penalties for his side.
While many fans have called for the talented youngster to receive more minutes, Puig has been used sparingly this season by Barca head coach Ronald Koeman.
Puig came off the bench against Sociedad on Wednesday for just his seventh appearance of the season, all of which have come as a substitute.
Although his chances of consistent minutes still appear to be slim, Puig said after the game that he would continue to fight for his place at Camp Nou.
“I’m very happy to have scored the last penalty,” Puig said. “I volunteered to take it. I shot with great conviction – you have to believe in yourself. I have never lost the desire to be in the first team and I will continue to fight for it.
“Ronald named four players to shoot the penalties. I asked for the fifth one. I’m a very happy guy, I have never lost my smile. I’m lucky, I will never give up.”
Koeman confirmed that Puig had volunteered to take the decisive spot-kick.
He said: “The final penalty? I had four names written down, and I asked who wanted to shoot the last one to win. Riqui wanted to take it, with determination.”
Koeman also had praise for two other 21-year-olds who have broken through with Barca this season, Ronald Araujo and Oscar Mingueza.
“Araujo has improved a lot in a short time, especially in how calm he is and his personality,” Koeman said. “He has also improved on the ball. He’s on a very good path, but he has to keep working. He’s the future of the club, like Mingueza. Be humble and keep your feet on the ground.”