Carissa Moore is through to the last eight after beating Alyssa Spencer ©Getty Images

Defending champion Carissa Moore has defeated Alyssa Spencer of the United States to reach the last eight of the women's draw at the World Surf League (WSL) Championship Tour event at Bells Beach in Australia.

Spencer was unable to pull off a shock upset against the Olympic champion following a round of 16 head-to-head which consisted of 11 waves.

Hawaii’s Moore put together a comprehensive score of 14.60 following six wave attempts while the American failed to score above five on three of her attempts to fall short.

She finished on a tally of 12.07.

Moore is expected to face Australia’s Stephanie Gilmore in the quarter-finals after the Australian beat her compatriot, India Robinson, in her round of 16 match-up.

In the fourth heat, Gabriela Bryan of Hawaii was completely blown away against Australia’s Tyler Wright, who scored the highest total of the round with 17.24.

Wright is now due to go head-to-head with fellow Australian Bronte Macaulay after she cruised past Brazil's Tatiana Weston-Webb by 4.76.

Others to progress into the next round included American Courtney Conlogue, Australia’s Sally Fitzgibbons, Costa Rica’s Brisa Hennessy and France’s Johanne Defay.

Conlogue, who finished second in the 2015 and 2016 WSL Championships, beat Lakey Peterson by a comfortable margin of 4.83 in the all-American tie.

Fitzgibbons edged Malia Manuel of Hawaii while Hennessy defeated Luanna Silva, also of Hawaii.

Defay knocked out Australia's Isabella Nichols to book her space in the last eight.

The WSL Championship Tour is due to continue tomorrow.