Australia's three-time world champion Mick Fanning faces a sudden-death heat after falling short in round one of the World Surf League event in Brazil.
World No.2 Fanning's combined-wave score of 9.33 out of 20 wasn't enough against local Italo Ferreira, who logged 14.07 in clean conditions to comfortably take out the heat in the Rio Pro on Tuesday.
It means Fanning will have his head on the chopping block when he lines up against another Brazilian David do Carmo in round two of the tour's fourth event.
Fellow Australians Bede Durbidge and Matt Wilkinson put on impressive showings to advance directly into round three.
Wilkinson produced a 14.96 to prevail in an all-Australian heat featuring Joel Parkinson (13.47) and Owen Wright (10.34).
But it was 11-time world champion Kelly Slater who found unparalleled rhythm in his victory over Australian Adrian Buchan (12.06) and Kiwi Ricardo Christie (11.76).
The American threaded barrels both ways to collect the day's high heat total of a 19.27.
"I felt really calm out there and in waves like that you just trust your instincts," Slater said.
World No.1 Adriano de Souza (17.90) progressed to the third round with a win in his opening heat over Australia's Kai Otton (11.60) and Brazilian David do Carmo (5.67).
In the women's event, defending two-time event winner Sally Fitzgibbons had a better time in her opening round, scoring 11.73 off the back of an early seven-point ride to beat compatriot Laura Enever (4.67) and France's Johanne Defay (8.00).
"I love coming here, it's been kind to me over the years and I've had some good results," the 24-year-old said.
Australian wildcard Keely Andrew, who replaced the injured Stephanie Gilmore, came out firing with a score of 11.07 to sail past Hawaii's Coco Ho (8.53) and Tyler Wright (9.83).
The result relegates Wright, who currently sits fourth in the tour rankings, to an elimination heat against Brazilian Luana Coutinho.
Australians Nikki Van Dijk, Laura Enever and Dimity Stoyle will also be looking to save their skins in sudden-death round-two match-ups.
