MATCH REPORT: Marsh fires Aussies into ODI final
The result saw Australia bounce back from a humiliating defeat at the hands of Zimbabwe at the weekend and assured them of a place in the triangular one-day series final.
But they could have been struggling had it not been for the big hitting of Marsh (86), whose late flurry of runs helped Australia to a total of 282-7.
"Very happy today," said Bailey, who scored 32 while Phillip Hughes' 85 was the second highest Australia total. "Luckily some great hitting form Marsh helped us put up a pretty competitive score. We were probably near the par total.
"We lost [Phillip] Hughes and myself at key times and Marsh got us to a big total."
South Africa's response was lacklustre, with the exception of Faf du Plessis, who racked up 126 runs before inadvertently clipping the wicket with his own foot.
"Faf's in unbelievable form and I was impressed with our energy and our players did the right thing at the right times," added Bailey.
"We got to get better with adjusting to conditions and we are looking forward to the final."
Bailey captained the side in the absence of Michael Clarke, who returned to Australia for treatment on a hamstring injury but Tweeted his congratulations and an update on his condition.
"Great win boys," he said. "Very proud of the way we have come back after our loss the otherday.
"@mitchmarsh235 all class. Great TEAM effort.
"Had a scan on the hamstring, some damage as expected but I will be back fitter and stronger.
"I have some great people helping me get my injury right. I will do whatever it takes to get back on the field with the boys."