Australia's world title leader Tyler Wright has endured a disappointing start to the World Surf League event at Lower Trestles in California.
Wright finished last in her opening-round heat of three on Wednesday (Thursday AEST), and will now have to compete in a sudden-death second-round battle.
In swell of less than a metre, Wright completed a number of low-scoring rides for a combined score 8.43 to be comfortably beaten by compatriot Nikki Van Dijk (13.53) and Hawaiian Bethany Hamilton (13.13).
She'll now face Hamilton again in the do-or-die second-round battle.
"It's not quite an upset to me knowing there's a lot of contest left and that was only one heat," Van Dijk said.
"But I'm stoked to move forward with a win and I'm just frothing on the chance to be out there with just a few other girls."
Wright's frustration would have eased slightly when the other main contender for the title, Courtney Conlogue, was also forced into sudden-death battle after losing her heat to Australian Laura Enever.
Enever kept busy in the water, surfing eight rides to Conlogue's two, and was able to produce scores of 7.57 and 6.40 to win by 2.37 points.
Six-time world champion Australian Stephanie Gilmore was the only other Australian to automatically qualify for the third round, producing the highest heat score of the day with rides of 8.50 and 8.20.
Sally Fitzgibbons and Keely Andrew will also face sudden-death heats when surfing resumes on Thursday (Friday AEST) after they finished last in their round battles.
