Ewing thrives in Rio surf, Robinson a shock casualty

Ethan Ewing is the last Australian man standing at the Rio Surf Pro, although Sydney-born Connor O'Leary has also advanced to the quarter-finals in Brazil.

But West Australian Jack Robinson was a shock round-of-16 casualty in six- to eight-foot swell at Praia de Itauna in Rio de Janeiro on Thursday (Friday AEST).

Ranked No.4, Ewing took on in-form Moroccan Ramzi Boukhiam and benefited from superior wave selection, only surfing two for a total of 13.67 to his rival's 8.50 from seven waves.

Ewing will face veteran Jordy Smith in the quarter-finals after the South African (12.10) eliminated another Australian, Ryan Callinan (7.30), in the round of 16.

Smith is ranked one place lower at world No.5 and desperate to keep a top-five position with just one event remaining before the World Surf League Finals in California in September.

After impressing in the opening round, Robinson fell to fellow Olympian O'Leary, who will compete under the Japan flag at the Paris Games.

The early exit means Robinson dropped one spot to No.3 in the world rankings.

Robinson got off to a slow start and was only able to manage a two-wave total of 8.40, while O'Leary scored 10.27 to set up a meeting with Italo Ferreira, who set alight his home crowd with a massive score of 17.50.

"I decided to surf," Ferreira said.

"I had a good score on my first four waves. I like to surf, you know, not to be, like, trying to find a wave. I try to catch a wave like every single moment and do my tricks and then push the limit, so that's what I did."

After surviving the elimination round, top-ranked John John Florence found his groove in the round of 16 to take down fellow Hawaiian Seth Moniz, 14.44 to 8.00.

He faces defending champion Yago Dora in the quarter-finals, while American world No.2 Griffin Colapinto will square off with Brazil's Gabriel Medina.

The women's draw remains on hold, with Australia's world No.4 Molly Picklum set to tackle Hawaiian Gabriela Ryan in the quarter-finals.