And she used the occasion to help spread a message of visibility and awareness for the LGBTQI community by wearing special rainbow-coloured head gear as the team began its quest for back-to-back gold.

Williams, who skippers the team, told Channel Seven afterward she was "a bit emotional" after the match.

"It's quite a journey and very, very special to me," she said.

"My community is behind me out there and this (headgear) doesn't just protect me and give me confidence when I go out there, but (hopefully) it gives some kid who is out there struggling with visibility and who they are that courage to come out and accept themselves."

Australia became the first women's rugby sevens Olympic gold medallists at Rio in 2016, and are shaping as one of the teams to beat once again.

They scored eight unanswered tries in their first game on Thursday afternoon, scoring 24 points in each half in a dominant 48-0 win.

They backed up that display with a 26-10 victory over China on Thursday night. They finish their pool games against USA on Friday morning (11.30am AEST) before the quarter finals are played early Friday evening.

Medal matches will be played on Saturday.

Meanwhile the Kookaburras, featuring Wagga's Dylan Martin, continued their brilliant start to the campaign with a hard-fought 4-2 victory over New Zealand on Wednesday night.

Martin was among a handful of players rested after Australia's world number one-ranked hockey side won their first three matches in Tokyo.

But it mattered little as the Kookaburras dug deep in the second half to continue a long-running winning streak against their Trans-Tasman rivals.

Tim Brand put Australia in front with a nice flick in the ninth minute, but the Black Sticks levelled scores soon after through Kane Russell off a penalty corner.

Australia struggled to break down New Zealand's defence in the middle period of the game, but with ten minutes to go Brand scored his second to give the Kookaburras the lead.

Further goals to Blake Govers and Tom Wickham sealed the win, before Russell added a late consolation for the Kiwis.

Australia completes its pool games against Spain on Friday morning (11am AEST), with quarter finals to be played on Sunday.