The Diamonds are the only undefeated team after victory over England in London as they bid for a third netball Quad Series title.
Australia prevailed 50-46 in a hard-fought tussle on Monday night at London's Copper Box Arena.
Goal-shooter Caitlin Bassett shook off a defensive double-team from English Super Netball stars Geva Mentor and Ama Agbeze to score 30 goals from 32 shots.
Bassett was well supported by Stephanie Wood (14 goals).
The Diamonds led into every break but their seven-goal halftime advantage was cut to three by the end of the third quarter after the Roses went on a run of six unanswered goals.
Coach Lisa Alexander brought Caitlin Thwaites into goal-shooter in the final quarter, with the veteran firing five-from-five goals to see off the hosts' challenge.
"One of the things we talk about is to look to each other, and change things up if we need to," Alexander said.
"When our opposition gets a bit of a run on, sometimes we need to change things in attack and defence. We did that a few times with positional switches.
"That's part of being part of a team. They understand that all of them will have different roles to play at different times."
Australia are top of the ladder after opening their campaign with a win over South Africa.
They travel to Johannesburg for Tuesday's match against arch-rivals New Zealand, who lost on Saturday to England, to wrap up their campaign.
