Olympics-bound Jack Robinson is flying the flag for Australia in the men's competition at the Surf City El Salvador Pro, with men's No.1 John John Florence keeping a tight hold on the yellow jersey.

Surfing in the eighth stop on the World Championship tour on Friday got off to a shock start with local wildcard Bryan Perez taking down world No.5 Italo Ferreira.

The Brazilian, the 2019 world champion and Olympic gold medallist, was fresh off a victory at the Tahiti Pro last week but Perez clinched the heat win with a massive air that scored 8.83 in front of his hometown crowd.

But top-ranked John John Florence put a halt to Perez's giant-killing run in the round of 16 to secure the yellow leader's jersey moving into Rio, the next stop on the CT.

"Seeing him on that set and it looked like the biggest, cleanest wall and everyone is cheering for every turn thinking it's a 10, I'm done," Hawaiian Florence said.

"It was really about just holding it together until they dropped the scores.

"Quarters is awesome and I'm stoked, but I'm here to win and have fun."

Robinson won a tight round-of-16 battle with Sydneysider Connor O'Leary, who will be surfing under the Japanese flag at the Paris Olympics.

The West Australian's two-wave total was 15.00 to edge O'Leary's 14.33 to set up a quarter-final showdown with Brazil's Yago Dora.

Current world No.4 Ethan Ewing, who will join Robinson at the Olympics, scored 13.76 and was eliminated by South African Matthew McGillivray (16.40).

McGillvray's fellow South African, CT veteran Jordy Smith also marched into the last eight, jumping into the No.5 position on the rankings with his win over Italian Leonardo Fioravanti.

Second-ranked Griffin Colapinto suffered a costly non-priority interference in his round-of-16 match-up with Joao Chianca, meaning he lost half of his backup score.

The American fought back, sending it for a 9.43, to stay in the heat but his last effort fell short of the 9.77 required.

Gabriel Medina vaulted up five spots to seventh on the rankings after the three-time world champion's backhand saw him score 16.17 to outpoint Australia's Ryan Callinan (15.00).

The women's competition is also up to the quarter-final stage with Australia's world No.3 Molly Picklum squaring up against Hawaiian Gabriela Bryan, who is currently ranked sixth.