Local surfer Jessi Miley-Dyer gave herself a massive boost going into her first year on surfing's pro tour by being crowned the inaugural women's world junior champion in Sydney on Thursday.

In a dream all-Australian girls final at North Narrabeen the 20-year-old beat Nicola Atherton in a contest that went down to the final wave in the one-metre surf.

The two girls were more than familiar with each other's moves as both call Bronte their local break.

Miley-Dyer did all the work early, recording her two scoring waves (7.78 and 6.17) in the first five minutes.

Atherton found herself with no score halfway through the heat before launching herself into contention with an 8.17.

Needing a 5.83 with only a few seconds to go, Atherton found a wave and slashed her way towards the beach but could only manage 4.23.

Miley-Dyer revealed her heart was in her mouth as Atherton rode the final wave.

"I didn't hear the score and I'd seen the wave from behind and I was like ... it's not a bad wave."

"A five-point ride in surfing is actually an average wave so I was thinking it could have been an average score.

"I didn't hear the score get read out but I saw my Dad on the beach and I was looking to my family for guidance ... and I was like, ah yes.

"It's such a terrible thing to be wishing someone doesn't get a score but it had to be done."

Miley-Dyer is looking forward to her first year on the World Championship Tour this year after coming third in the qualifying series.

She is confident she can move up the ranks and mix it with the world's best, including the legendary Laine Beachley.

"My focus this year is going to be on (the WCT). I think I am currently ranked No.15 going into the year so I'll be looking to improve that ranking and hopefully make the top six."

Meanwhile, only two Australians will head into Friday's final day of the men's junior titles.

The Gold Coast's Dion Agius and Copacabana's Matt Wilkinson are both through to round four of competition after Agius accounted for American Spencer Stirling and Wilkinson outpointed tournament favourite Jordy Smith of South Africa.

Rhys Bombaci, Beau Walker and Laurie Towner, who lost to defending champion Pablo Paulino of Brazil, were all eliminated.

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