Chelsea took the lead at Stamford Bridge through a Jules Kounde own-goal in the 27th minute having already had two goals ruled out for offside.
Things got worse for Barcelona just before the break with Ronald Araujo picked up a second yellow card for a rash tackle on Marc Cucurella.
Ahead of the game, all the talk was about Estevao, 18, and Lamine Yamal with the Chelsea man coming away with a memorable win.
Speaking to Amazon Prime about his goal, he said: "I don't really have any words to sum up how I'm feeling right now. It really was the perfect night. I'm just grateful to God for everything that has happened for me. Onwards and upwards from here.
"It all happened very quickly for me, it sort of happened before I knew it. I just found some space, wiggled my way through and then scored that goal. It was such a special moment for me in my career. I hope to score many more.
"It was definitely the best moment of my career so far. I want to score many more for many years. I'm so grateful that my family were here watching me.
When asked about his connection with the fans, he added: "From the moment I arrived here, I felt such a connection with the fans. I'm just so happy that I could score for them and make them happy. I hope to keep making them happy and score more goals for them."