Australian star Jack Robinson has turned in the best wave of the Olympic surfing on his way into the last 16 in Tahiti.
Molly Picklum wasn't so lucky, surviving a run-in with the reef but not her heat, exiting the competition in the second round at Teahupo'o.
Robinson waited out a long lull in the French Polynesian waters on Monday (AEST) in his second-round heat with Peru's Lucca Mesines.
When the waves did come, the Western Australian capitalised, dropping into a mighty barrel and sticking the ride, earning 9.87 for his efforts: the top single wave score of this year's Olympics.
Paddling hard to optimise his positioning into another big breaker, Robinson finished with 16.87, clear of Mesines on 10.83 and enough to win the knockout duel.
He joins fellow Australians Ethan Ewing and two-time world champion Tyler Wright in round three, while Picklum wasn't so lucky on a fickle day in the water.
In a clash of two in-form stars of the World Surf League, Frenchwoman Johanne Defay, ranked sixth, edged the fourth-ranked Picklum 11.83 to 7.43.
Defay, 30, made the early running to put the 21-year-old under pressure, who then chased a long barrel all the way into the shallows to complete a combination ride to maximise her score.
When she bailed from the surf, she showed the peril of the infamous and dangerous French Polynesian break: standing up in ankle-deep water.
"It was rock dance at the end but you want to put it all on the line for your country," she said.
That ride produced her best score of the heat, 5.83, but Picklum needed another similar-scoring ride to top the Frenchwoman.
Instead she bobbed up and down out the back of a few sets, watching the minutes tick down without a barrel she felt she could score heavily on, passing up the chance to progress.
"Sometimes the waves don't play their part," she said, throwing her support behind her compatriots.
"Even though it's not me I still want an Aussie to bring home a gold.
"I'm staying with Jack so I'll be washing his dishes, cooking him breakfast, anything to get him over the line."
Ewing and Wright won their first-round heats to skip round two, and will re-enter the competition - waves permitting - on Tuesday (AEST).
With unfriendly winds forecast, some are tipping a lay day which could push out the final two days.
Tuesday is scheduled to host the round of 16, and Wednesday, the bumper finals day when the final eight all compete in knockout ties through to the medal rounds.
Wright has been drawn against Israel's Anat Leilor in the round of 16, while Ewing and Robinson will know their opponents later on Tuesday after the completion of the men's second round.
