Moore took gold at Tokyo 2020 representing the United States, and competes under the Hawaiian flag in the WSL.

She is the defending and five-time WSL champion.

Moore scored 6.00 on the first wave and 7.67 on her fourth to finish with a total of 13.67 points, beating the 12.53 recorded by Australian home favourite Stephanie Gilmore.

The Hawaiian is now set to face the only surfer ranked above her on this season's leaderboard in the semi-finals, after Costa Rica's Brisa Hennessy edged past Johanne Defay of France by 11.60 to 11.57.

Tyler Wright is the only Australian remaining in the women's event at Bells Beach after impressive scores of 8.17 and 9.00 sent her through with a total of 17.17.

Her compatriot Bronte Macaulay notched 12.07 so was eliminated.

Wright is due to face Courtney Conlogue of the US in the semi-finals after she scored 14.57 to the 11.93 of Australia's Sally Fitzgibbons.

Conlogue is a three-time winner at Bells Beach and has tasted victory in three of the last four editions of this event.

The men's Olympic champion also progressed as Brazil's Italo Ferreira overcame compatriot Samuel Pupo by 15.40 to 15.13.

A quarter-final against Jack Robinson awaits him after the Australian eased past Hawaii's Imaikalani deVault with 16.04.

Filipe Toledo of Brazil, fourth on this season's standings, remains the highest-ranked surfer remaining at Bells Beach after he posted 16.26 to see off Australia's Connor O'Leary.

Toldeo is due to face John John Florence in what looks an exciting quarter-final.

The Hawaiian was the top scorer of the day with 17.77 against Australia's Morgan Cibilic.

Australian wildcard Mick Fanning's run came to an end after he lost to compatriot Callum Robson by 14.50 to 14.27.

Robson has been pitted against Miguel Pupo of Brazil in the quarter-finals after he scored 14.76 to beat American Kolohe Andino.

An all-Australian tie completes the line-up for the last eight after Olympic bronze medallist Owen Wright and Ethan Ewing overcame American Nat Young and Jackson Baker of Australia respectively.

Bells Beach is the penultimate event on this year's WSL Championship Tour before the mid-season cut.

Several surfers have signed a petition urging the WSL to reconsider the move which would end the season for all but the top 24 men and 12 women, but chief executive Erik Logan appeared to rule that out.

"I want to be very clear that it is inconceivable that we could, should or would eliminate the mid-season cut, which is the foundation of our redesigned Championship Tour," Logan said in response to the surfers, as reported by Reuters, also claiming that eliminating the cut would put the WSL in danger of breaching some contracts.