The 18-year-old impressed on the lefthand ramps of Lower Trestles early in the day before taking the day's highest single wave score of 9.87 on his way to a near-perfect heat total of 19.53 in his round of 24 heat.
“That was fun and both the lefts and rights are pretty good,” Medina said. “I had a good heat and I think it’s because I woke up really early, at five in the morning, and got down here in the dark.
"I think it helped me get ready for my heat. The non-elimination round is great because it’s no pressure too because everyone can show how they surf.”
Fellow Brazilian Heitor Alves was another goofy surfer to stamp his authority on the steep lefthand wall at Lowers.
“I had a great time again, I really like this wave and I just tried my best out there and won my heat.” Alves said.
“I surfed before my heat and knew the sets were slow and I wanted to wait for the best ones and I got lucky.”
Heat 1: Fredrick Patacchia (HAW) 17.13, Glenn Hall (IRL) 15.03, Jeremy Flores (FRA) 14.77
Heat 2: Nat Young (USA) 17.17, Sebastien Zietz (HAW) 13.86, Tomas Hermes (BRA) 13.26
Heat 3: Tanner Gudauskas (USA) 17.87, Gabe Kling (USA) 15.50, Taylor Knox (USA) 12.23
Heat 4: John John Florence (HAW) 16.23, Cory Lopez (USA) 15.67, C.J. Hobgood (USA) 13.06
Heat 5: Gabriel Medina (BRA) 19.53, Daniel Ross (AUS) 13.06, Dane Reynolds (USA) 12.33
Heat 6: Granger Larsen (HAW) 18.43, Heitor Alves (BRA) 17.00, Brett Simpson (USA) 14.74
Heat 7: Adrian Buchan (AUS) 15.17, Jay Thompson (AUS) 13.60, Blake Thornton (AUS) 13.20
Heat 8: Patrick Gudauskas (USA) 15.53, Mark Occhilupo (AUS) 13.83, Nathan Yeomans (USA) 8.57
Heat 7: Gabriel Medina (BRA) 16.90, Granger Larsen (HAW) 16.77, Mitch Crews (AUS) 13.93, Charles Martin (GLP) 6.87
Heat 8: Brett Simpson (USA) 16.60, Dane Reynolds (USA) 15.30, Heath Joske (AUS) 13.80, Jesse Mendes (BRA) 12.27
Heat 9: Heitor Alves (BRA) 17.70, Daniel Ross (AUS) 13.27, Alejo Muniz (BRA) 13.00, Kiron Jabour (HAW) 7.66
Heat 10: Jay Thompson (AUS) 15.60, Patrick Gudauskas (USA) 15.13, Conner Coffin (USA) 11.90, Jano Belo (BRA) 10.10
Heat 11: Adrian Buchan (AUS) 15.10, Nathan Yeomans (USA) 14.53, Romain Cloitre (FRA) 13.77, Hank Gaskell (HAW) 11.87
Heat 12: Mark Occhilupo (AUS) 14.10, Blake Thornton (AUS) 13.83, Tom Whitaker (AUS) 10.17, Michel Bourez (PYF) 6.40