The two fast bowlers returned combined figures of 8/52 (Parnell 4/25 and Steyn 4/27) as Australia were routed for 131.
The target was never going to trouble the Proteas who cruised to victory by seven wickets after using up just over half of the overs available. There were still 142 balls available when the match ended.
It levelled the series at 1-1 with three matches to play after the Australians equally comprehensive victory at Sahara Stadium Kingsmead on Friday with the next match to be played at Sahara Park Newlands on Thursday.
Not surprisingly national selection chief Mike Procter has named an unchanged 15-man squad for the next two matches.
Parnell was a popular choice as MTN man of the match in only his second ODI. His four victims included Australia's big three of Ricky Ponting, Michael Clarke and Michael Hussey and at one stage his new ball spell read 4-3-3-3. He bowled an incredible24 dot balls in his opening spell of 5-3-12-3.
“Wayne gave us an exciting glimpse of his potential today,” commented captain Graeme Smith. “He has benefited enormously from being part of the national squad both in Australia and again here in South Africa since joining us for the third Castle Test match.”
Parnell paid tribute to the work national bowling coach Vinnie Barnes has done with him since he came into the national squad and said that the biggest lesson he had learned was to concentrate on his basics at all time.
The only Australian batsman to keep the rampant Proteas' attack at bay for any length of time was Callum Ferguson (50 off 83 balls, 3x4) and he was eventually eighth man out when Steyn came back for the kill and surprised him with a short delivery that was brilliantly caught by AB de Villiers, running in and diving forward from the point position.
Australia's only chance of a fightback rested with Mitchell Johnson and not surprisingly Ricky Ponting bowled him out in the short time that South Africa took to finish off the match.
It was Australia's fourth lowest total against South Africa and confirmed SuperSport Park as one of South Africa's favourite home venues where they have won 15 out of 21 ODIs.
Herschelle Gibbs' catch to dismiss Nathan Bracken was his 105th for South Africa in ODIs and enabled him to draw level with Jacques Kallis and Jonty Rhodes as South Africa's most successful fielder in this format of the game.
