"We allowed their frenetic play to infect us and affect our composure at times," she said. "Our decision making went out the window - that was a little bit disappointing but it certainly points towards a few things that we need to fix for the next test against England," Alexander said.
"Too many times we were looking down at one option and putting pressure on that instead of using our swings and our double plays and our ball movement."
Though a more closely contested quarter, Australia led by 11 goals at half time.
The Diamonds pushed that lead out to 45-30 heading into the final spell as they tightened up their attacking play and began to exert more full court pressure on the home side.
The Proteas responded by finishing with their best quarter of the game, matching the Diamonds virtually goal-for-goal in a high-scoring final spell. Australia just won the final quarter 17-16.
The Quad Series now moves to England where the Roses will take on the Silver Ferns on Friday morning, before Australia and South Africa join them in London for a double header next Monday.