Organisers in Portugal called a lay-day on Saturday in order for the surfers to make use of optimal conditions for the quarter-finals, semi-finals and final of the ASP 6-Star event.
And an overnight swell offered four-to-five-foot waves.
Felix started slowly in the final but a 7.93 lefthander saw him claim back the lead then a 7.00 righthander sealed the contest, his maiden Star win.
"I'm so tired right now and I can't really explain how I feel," Felix said.
"I'm over the moon you know, this is my first time winning a big Star event, and it was against my best friend Wiggolly, we're staying together here and always driving together to the beach in the car etc.
"I just want to thank God for being here with me all the time and for looking after me and my family. I know everybody at home is probably watching this on the internet and they must be going crazy - there's going to be a party in Brazil right now!"
Dantas said: "I feel good, but I know I blew it. It's still a great result a second here is perfect.
"I'm very happy for Messias. I had a good right and I thought I could make two turns, but the wave kind of barrelled and you know sometimes it's hard to read it - you plan something and something else comes."
1 - Messias Felix (BRA) 14.93
2 - Wiggolly Dantas (BRA) 13.27
Heat 1: Messias Felix (BRA) 13.00 def. Nat Young (USA) 11.80
Heat 2: Wiggolly Dantas (BRA) 15.90 def. Hodei Collazo (EUK) 5.93
Heat 1: Nat Young (USA) 14.83 def. Hizunome Bettero (BRA) 12.26
Heat 2: Messias Felix (BRA) 14.66 vs Tanner Gudauskas (USA) 10.33
Heat 3: Wiggolly Dantas (BRA) 13.63 vs Thiago Camarao (BRA) 11.33
Heat 4: Hodei Collazo (EUK) 15.66 def. Jonathan Gonzalez (CNY) 15.24