The 18-year-old had made two previous Serie A appearances off the bench this season before he was introduced at Marassi with the score still at 0-0.
He made the most of a Henrikh Mkhitaryan assist, then added a second in stoppages with a sensational curler into the far top corner.
Felix is the first player born in 2003 to find the net in Serie A, let alone to bag a brace, and even he seemed incredulous.
“I thank God for this opportunity he gave me, the team, the coach, the fans, players for their amazing support. I also want to say thank you Mom, she is in Ghana, I love you,” Felix told DAZN after the final whistle.
Naturally, Felix ran straight to the touchline to hug his coach Mourinho, who plucked him from the Roma Primavera youth team to boost their numbers.
“Mourinho is a great person, a great manager and a great coach. He gives you the motivation to learn every day. I am very happy he is here.
“Tonight is a dream come true. It was my first goal, I was hoping for a very long time. I want to continue my performance, prove myself and do more in future.”
😱 OH MY WORD!
Felix Afena-Gyan unleashes an absolute thunderbolt to seal the win for Roma 🚀
Two goals in 12 minutes for the 18-year-old! 👏 pic.twitter.com/gLsLPYdOkr
— Football on BT Sport (@btsportfootball) November 21, 2021