The win in lightweight double meant the most to Cox. She and Waikato's Justine Hobbs put in a dominant display, storming home to beat the Australians by 13 seconds.
"I'm really happy with that, it's a good outcome.
"The lightweight was our main event, we really wanted to be winning that one."
She said their time, seven minutes and 29 seconds, was "pretty on target".
Her and Hobbs teamed up with the heavyweight double to race in the mixed women's quad and tasted success there too.
Then the four of them joined forces with four NZ girls who compete in sweeping events, to race in the eight.
"We came from behind in the eight. They were ahead for the first 1500 metres, that last 500 metres we picked it up and turned it around."
Cox said she enjoyed racing in eights as coming from Whangārei where rowing numbers are small, she hadn't really been in the bigger boat.
However, the lightweight double is where she sees her future.
The two countries compete for the Rusty Robinson Trophy. Cox said New Zealand have lost the trophy for the past four years but the team is just two points behind heading into the second leg.
"It's the closest we've been in the past four years. It will be good to hopefully get it back this year."
The second leg of the regatta is at Lake Karapiro in August.
Cox, who is now based in Christchurch training at the southern regional training centre ,is very determined. She is stoked with this success, but just wants to keep going.
"My goal is to do the under-23s next year, which is another step up from what I'm doing now."
She said that includes a trip to Europe.
Dad Kelvin Cox said he was very proud of his daughter.
"She's looking like she can go further with her rowing.
"Now she's in the Rowing New Zealand system, she's getting the support from them."
He followed his daughter's racing in Sydney online, but said he'll save up to make the trip to Europe next year if she makes it.
