Australia are one win away from a 12th Netball World Cup triumph after seeing off a spirited South Africa side in an enthralling semi-final in Liverpool tonight.
The Diamonds, who ran out 55-53 winners, were made to fight all the way by the Norma Plummer-coached Proteas who were looking to reach the final for the second time in their history.
Lisa Alexander's side will now face either New Zealand or hosts England in Sunday's decider.
Alexander made five changes to the side that edged out the Silver Ferns on Friday with skipper Caitlin Bassett and Steph Wood dropped to the bench as Caitlin Thwaites and Gretel Tippett filled the goal shooter and goal attack roles.
South Africa started strongly in a keenly-contested opening quarter, as both sides turned the ball over regularly in the opening exchanges.
The Proteas were made to pay for missed chances from under the hoop by Lenize Potgieter as the Diamonds scored two quickfire goals to open up a 14-10 lead at the start of the second stanza.
The Diamonds slowly started to exert some dominance with Tippett causing South Africa all sorts of problems in the attacking third of the court as they stretched their advantage to 31-23 at halftime.
However, Plummer's message to her players during the interval had the desired effect as the Proteas won the third quarter to close the gap to 43-39 going into the final 15 minutes.
Once again their shooting let them down with Potgieter and Maryka Holtzhausen spurning opportunities as the Diamonds defence tried to hold firm.
Alexander replaced the impressive Tippett, who was flawless from 23 attempts, with Steph Wood as South Africa, galvanised by their strong third quarter closed the gap to one goal with 10 minutes remaining
However, the vastly experienced Thwaites held her nerve to score a crucial goal to restore the three-point gap after a crucial intercept from defender Watson.
But South Africa continued to fight back and a Potgieter goal reduced the deficit to a single goal but the Diamonds, led superbly by Thwaites (30/30) closed out a tense encounter.
"It was really tough we felt momentum swings switching but we managed to find another level," Thwaites said.
"I feel like it was good, but we have so much to improve on."