After months of turmoil, finally this team had the opportunity to make a statement on the pitch.

That they did, toppling Spain 3-1 in a hard-fought affair.

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While many wrote the Hockeyroos off before the competition commenced, goal-scorer Emily Chalker said their rivals should be wary.

"The Aussie underdog, 'never give up' attitude, aggressive style of hockey," Chalker said when asked what their opponents should expect.

"We go hard and we fight until that last minute and I think that's what everyone will see when they watch the Hockeyroos.

"We've been training hard, working hard and to put out a very skilful but also controlled performance - knowing when to attack (and) knowing when to just hold the ball and play in the heat."

The Australians are not getting ahead of themselves, Spain are ranked below them in the world rankings and it's only the first match of a two-week tournament.

But the early signs are promising.

Katrina Powell has had just four months with the side after she took over a squad in crisis in late March.

Allegations of bullying and abuse had been directed at the team's officials, with coach Paul Gaudion standing down after a comprehensive review of the program.

Among the features of the investigation was the treatment of experienced goalkeeper Rachael Lynch, the 35-year-old initially left out of the national squad.

An appeal saw her added to the program in April and there she was in Tokyo playing a starring role to limit Spain to just one goal with a number of superb saves.

From the moment Powell took charge, the Hockeyroos presented a united front. The turmoil of past years was in the rear-view mirror, now was the time to focus on their ultimate goal, Olympic gold.

The chance to achieve that goal has arrived and Sunday marked a promising first step.

From here, the Hockeyroos must turn their focus to another winnable game, the team playing China on Monday.

Sunday's clash was the definition of a game of two halves, the first a tight scoreless affair before the match opened up immediately after the break.

Three goals were scored in the space of three minutes, Australia holding a 2-1 lead before Gerringong's Grace Stewart made it 3-1 with a brilliant diving effort.

The fourth quarter was another tight period, Spain pushing the narrow the gap while the Hockeyroos fought to maintain their advantage.

The Europeans had a number of chances, however Australia were resolute in defence throughout the final 15 minutes to hold firm and secure a 3-1 victory.

With one win in the bag, it's now time to keep building towards the medal rounds.

"(It was) a bit of a nervous start," Chalker said. "To be able to put three goals in your first Olympic game we've been training so hard for, is going to give everyone a bit of confidence, settle the nerves and then we'll go full steam ahead from here."