Arrambide, 23, earned the monster score with an incredible front side inverted aerial to advance ahead of Messias Felix (Brazil).
In the highest scoring heat of the event so far, Jay Thompson (Australia) and up-and-coming prodigy Filipe Toledo (Brazil) were defeated despite both having a high score on the board.
"I'm so stoked," Arrambide said.
"I was struggling at the beginning, couldn't find the rhythm of the ocean and I was watching Bottle just hacking these rights and finally I just changed my whole plan and moved down the beach, and I caught a good right and then straight into that left.
“I don't usually claim a wave but there was just too much adrenalin running, and I was psyched. That was a good heat, I'm stoked!"
Arrambide caused the biggest upset today defeating rising star Toledo at his own game using aerials to beat two Brazilians in their third round exchange.
With all four surfers scoring over 13.80, Arrambide had to bust out the big guns to make a difference and landed the biggest and most radical aerial seen so far in the SATA Airlines Azores Pro.
"Usually in most contests I rely on some little air reverses on the lefts, cause recently my backhand has been giving me scores,” he added.
“But I've been waiting to pull out a good air on my front side, and those lefts down the beach were standing up today.
“It was a bit weird, I saw that left and I knew it was going to be a good one, but when I stood up my back foot was kind of in the wrong spot but I just went for the air on the first section and I got some good height and I stuck it so I was stoked."
Felix, 26, coming second behind Arrambide, was again one of the most impressive surfers, scoring both the second highest single wave and second combined heat total of the event so far, to move into the next round of competition ahead of former World Championship Tour contender Thompson and potentially-qualified Toledo.
"I'm stoked to advance through that one, cause at the end there I got really nervous with Cory having those two huge scores, Filipe right behind with a big one too,” Felix said.
“I knew before we started that this was going to be one of the hardest heats of my life with all those guys out there and I think tomorrow I'll wake up feeling good and will try to advance heat by heat a few more.
“You know, from now on, every heat is harder than the previous so I'll have to see how it goes."
REMAINING ROUND OF 48 MATCH-UPS:
Heat 9: Jean Da Silva (BRA), Stu Kennedy (AUS), Thiago Camarao (BRA), Simao Romao (BRA)
Heat 10: Ty Watson (AUS), Caio Ibelli (BRA), Cristobal De Col (PER), Nat Young (USA)
Heat 11: Hodei Collazo (EUK), Maxime Huscenot (FRA), Charles Martin (GLP), Matt Wilkinson (AUS)
Heat 12: Fredrick Patacchia (HAW), Marc Lacomare (FRA), Jonathan Gonzalez (CNY), Marlon Lipke (DEU)
ROUND OF 48 RESULTS:
Heat 1: Tiago Pires (PRT) 11.67, Brian Toth (PRI) 10.40, Evan Geiselman (USA) 9.13, Steven Pierson (PYF) 6.10
Heat 2: Tim Macdonald (AUS) 11.50, Eric Geiselman (USA) 10.47, Alain Riou (PYF) 10.17, Frederico Morais (PRT) 8.27
Heat 3: Nat Young (USA) 14.54, Hizunome Bettero (BRA) 12.93, Alan Donato (BRA) 10.17, Gony Zubizarreta (ESP) 7.67
Heat 4: Sebastien Zietz (HAW) 11.93, Krystian Kymerson (BRA) 11.23, Jano Belo (BRA) 7.73, Romain Cloitre (FRA) 5.20
Heat 5: William Cardoso (BRA) 11.66, Tanner Gudauskas (USA) 11.03, Joan Duru (FRA) 11.03, Lincoln Taylor (AUS) 5.87
Heat 6: Cory Arrambide (USA) 18.57, Messias Felix (BRA) 16.84, Jay Thompson (AUS) 14.44, Filipe Toledo (BRA) 13.83
Heat 7: Dion Atkinson (AUS) 13.43, Vincent Duvignac (FRA) 10.34, Santiago Muniz (ARG) 8.24, Yujiro Tsuji (JPN) 5.67
Heat 8: Wiggolly Dantas (BRA) 13.00, Granger Larsen (HAW) 12.76, Thomas Woods (AUS) 9.94, Glenn Hall (IRL) 9.33
ROUND OF 96 RESULTS:
Heat 5: Nat Young (USA) 13.34, Jano Belo (BRA) 10.03, Luke Davis (USA) 8.23, Manuel Selman (CHL) 6.53
Heat 6: Alan Donato (BRA) 11.93, Romain Cloitre (FRA) 8.74, Billy Stairmand (NZL) 8.54, Filipe Jervis (PRT) 4.67
Heat 7: Krystian Kymerson (BRA) 12.30, Hizunome Bettero (BRA) 10.50, Aritz Aranburu (EUK) 8.87, Jerome Forrest (AUS) 8.60
Heat 8: Sebastien Zietz (HAW) 12.50, Gony Zubizarreta (ESP) 11.87, Garrett Parkes (AUS) 11.77, Alexandre Chacon (BRA) 8.70
Heat 9: William Cardoso (BRA) 15.50, Cory Arrambide (USA) 14.73, Bernardo Miranda (BRA) 10.00, Eduardo Fernandes (PRT) 7.60
Heat 10: Joan Duru (FRA) 15.60, Messias Felix (BRA) 12.40, Miguel Tudela (PER) 9.93, Shaun Joubert (ZAF) 9.56
Heat 11: Jay Thompson (AUS) 12.33, Lincoln Taylor (AUS) 9.64, Guillermo Satt (CHL) 9.63, Ian Gouveia (BRA) 7.16
Heat 12: Filipe Toledo (BRA) 12.80, Tanner Gudauskas (USA) 12.67, Peterson Crisanto (BRA) 11.36, Masatoshi Ohno (JPN) 7.70
Heat 13: Santiago Muniz (ARG) 12.43, Glenn Hall (IRL) 10.67, Medi Veminardi (REU) 7.97, Jeffrey Lukasik (USA) 7.80
Heat 14: Dion Atkinson (AUS) 14.33, Thomas Woods (AUS) 11.50, Matt Banting (AUS) 5.67, Gavin Gillette (HAW) 5.47
Heat 15: Wiggolly Dantas (BRA) 15.27, Yujiro Tsuji (JPN) 11.23, Dillon Perillo (USA) 9.84, Nathan Hedge (AUS) 8.96
Heat 16: Granger Larsen (HAW) 14.27, Vincent Duvignac (FRA) 11.07, Ian Crane (USA) 10.90, Eneko Acero (EUK) 10.17
Heat 17: Jean Da Silva (BRA) 13.94, Ty Watson (AUS) 12.67, Flavio Nakagima (BRA) 9.85, Adrien Toyon (FRA) 8.33
Heat 18: Stu Kennedy (AUS) 14.30, Caio Ibelli (BRA) 13.50, Nobuyuki Osawa (JPN) 10.90, Teale Vanner (AUS) 8.10
Heat 19: Cristobal De Col (PER) 14.17, Thiago Camarao (BRA) 12.00, Keanu Asing (HAW) 11.00, Rudy Marechal (FRA) 7.07
Heat 20: Nathan Yeomans (USA) 10.90, Simao Romao (BRA) 10.66, Kiron Jabour (HAW) 9.56, Marco Fernandez (BRA) 5.57
Heat 21: Hodei Collazo (EUK) 11.30, Fredrick Patacchia (HAW) 11.26, Sidney Guimaraes (BRA) 9.50, Vasco Ribeiro (PRT) 8.00
Heat 22: Maxime Huscenot (FRA) 9.93, Marc Lacomare (FRA) 8.50, Alex Ribeiro (BRA) 8.27, Alan Jhones (BRA) 7.96
Heat 23: Jonathan Gonzalez (CNY) 13.34, Charles Martin (GLP) 10.03, Bruno Rodrigues (BRA) 9.10, Vicente Romero (ESP) 9.07
Heat 24: Marlon Lipke (DEU) 10.33, Matt Wilkinson (AUS) 9.56, David Do Carmo (BRA) 7.44, Nunes Weverton (PRT) 3.37