Australian Jack Robinson thrived in his home away from home but the biggest women surf stars were forced to do things the hard way on a day of upsets at the Rio Pro in Brazil.

After four consecutive lay days, powerful four-to-six-foot swell greeted surfers at Praia de Itaúna in Rio de Janeiro on Wednesday (Thursday AEST).

Australians Robinson and Ethan Ewing earned direct entry into the round of 16 after impressive opening-round displays.

Gabriel Medina, Italo Ferreira, Yago Dora, Jordy Smith and Seth Moniz were the other big names to cruise straight into the third round.

Two-time world champion John John Florence surprisingly finished last in his three-man opening heat, but he defeated Joao Chianca in the elimination round to also secure a spot in the round of 16.

World No.3 Griffin Colapinto also made it through the elimination round, along with Australian Liam O'Brien.

Ewing is fourth in the standings and Robinson sits second, giving them an excellent platform to snare a berth for the end-of-season finals, where the top five surfers will battle it out for the title.

Robinson's 7.00-point ride proved to be one of the day's highlights, allowing him to defeat countryman Ryan Callinan and Brazilian Samuel Pupo in their three-man heat.

The West Australian has strong ties to Brazil, with both his wife and coach coming from there."It's super good energy here," Robinson said.

"Everyone's super excited, and it feels like another home when I come here.

"I have everybody that I travel with all year. So yeah, I love it."

Brazilian trio Medina, Ferreira and Dora currently sit sixth, seventh and eighth in the standings respectively, but a big result in their home event could thrust them into the top five.

In the women's draw, world No.1 Caitlin Simmers, world No.3 Brisa Hennessy, world No.4 Picklum, world No.5 Johanne Defay and world No.6 Gabriela Bryan all failed to fire in the opening round, thrusting them into the elimination second round.

All apart from Defay managed to escape the carnage and book a quarterfinal berth.

Picklum will face Bryan in the quarters when competition resumes, while Simmers takes on Luana Silva, Hennessy is up against Tatiana Weston-Webb, and world No.2 Caroline Marks will be pitted against Sawyer Lindblad.

Australia's two-time world champion Tyler Wright pulled out of the event with a foot injury.

Given she is a lowly 10th in the live rankings and there's only one more regular-season event remaining after Rio, she's almost certain to miss the top-five cut for the end-of-season finals.