Smith showed an incredible variety of technical airs and turns in the final - launching a massive straight frontside air for a 9.33 and a stailfish air-reverse for an 8.50 to top De Souza for the win.
The Billabong Rio Pro victory marks the third career ASP WCT event win for Smith and his first away from South African soil.
"This win feels unbelievable,” Smith said.
“It’s another dream come true. I knew I could win a World Tour event, but I had to prove to myself that I could do it away from South Africa. Thanks to crowd and Adriano (de Souza). He’s been ripping the whole event. Thanks to all of my friends and family for all of the amazing support.”
Smith defeated dangerous rookie Filipe Toledo and two-time ASP World Champion Mick Fanning en route to the final.
Smith now sits at number two on the ASP WCT Rankings.
De Souza’s win at Bells Beach combined with his runner-up effort at the Billabong Rio Pro vaults the hard-working Brazilian to the number one position in the ASP WCT rankings.
1 – Jordy Smith (ZAF) 17.80
2 – Adriano de Souza (BRA) 16.34
SF 1: Adriano de Souza (BRA) 17.64 def. Gabriel Medina (BRA) 17.50
SF 2: Jordy Smith (ZAF) 14.83 def. Mick Fanning (AUS) 8.26
QF 1: Adriano de Souza (BRA) 15.33 def. Kelly Slater (USA) 12.30
QF 2: Gabriel Medina (BRA) 16.43 def. Adrian Buchan (AUS) 14.93
QF 3: Mick Fanning (AUS) 12.50 def. Sebastian Zietz (HAW) 12.37
QF 4: Jordy Smith (ZAF) 17.76 def. Filipe Toledo (BRA) 14.07
ASP WCT TOP 5 SURFERS:
1. Adriano de Souza (BRA) 18,500 pts
2. Jordy Smith (ZAF) 18,250 pts
3. Mick Fanning (AUS) 18,200 pts
4. Kelly Slater (USA) 16,950 pts
5. Taj Burrow (AUS) 15,700 pts