In reply Australia could only manage 219 before being bowled out in the 38th over.The defeat is the 5th heaviest by runs in Australia's ODI history.
Tremain did pick up his maiden ODI wicket late in the Proteas' innings, finishing with 1-78 off his 10 overs.Mennie claimed 0-82 from his 10 in a tough initiation to international cricket.
John Hastings (3-57) and Mitch Marsh (2-68) were the pick of the bowlers for the tourists. The difference in terms of pace and experience in the two bowling attacks was exposed in brutal fashion when Australia began their run chase.
Kagiso Rabada (2-31) and Dale Steyn (1-37) removed Aaron Finch (1) and Steve Smith (14) early before Wayne Parnell (3-40) chimed in with the wickets of George Bailey (9) and Marsh (19) to reduce Australia to 4-87.David Warner (50) and Travis Head (51) - with his maiden ODI half-century - were the only batsmen to pass the milestone in Australia's innings.
But when they fell as well as Matthew Wade (33), South Africa romped to another comfortable victory.Australia must now avoid defeat in the third ODI in Durban on Wednesday to keep the series alive.