The Australian skipper smashed an unbeaten 143 to add to his brilliant 120 two days earlier as the world champions stole an unlikely victory to complete a 2-0 series win.
The South Africans, needing to win the third and final match to square the series, gambled everything on a calculated last-day declaration that backfired horribly on them.
Graeme Smith [ Images ] aborted his team's second innings at 194-6 an hour before lunch, setting Australia a record run-chase of 287 off 76 overs to win, a required run-rate of 3.8 per over.
The odds were stacked in South Africa's favour. No team had scored more runs in the fourth innings to win a Test at the Sydney [ Images ] Cricket Ground. The previous record, set more than a century ago, was Australia's 276-4 to beat England [ Images ] in 1898.
But the Australians, playing the game like a one-day match, tore up the history books with a ferocious display of batting, racing to their target with almost 16 overs to spare and averting the threat of a late thunderstorm.
South Africa had made an encouraging start when Charl Langeveldt clean bowled Justin Langer for 20 in the last over before lunch but their hopes were dashed when Ponting and Matthew Hayden [ Images ] piled on 182 runs for the second wicket, including 150 in the middle session.
Hayden eventually fell for 90, caught by Smith at backward point off Johan Botha [ Images ], leaving Brad Hodge [ Images ] (27 not out) to finish off the job. But all the accolades went to Ponting, who was a unanimous choice for player of the match and the series.
The 31-year-old, now officially entrenched as the world's number one batsman, smashed 16 boundaries in a chanceless innings spanning 201 minutes off 159 balls, passing a series of important milestones along the way.
Ponting became the first player to score centuries in each innings of his 100th Test, taking his career tally to 28 Test hundreds and moving into sixth place overall, just one behind Don Bradman.
He lifted his career aggregate to 8,253 runs at an average of 57.71, overtaking Rahul Dravid [ Images ], Mark Waugh [ Images ], Garry Sobers, Inzamam-ul-Haq [ Images ], Geoff Boycott and David Gower to move into the all-time top 10 of Test run-scorers.
Ponting also became the first player to score five Test hundreds at the SCG as well as overtaking Allan Border [ Images ] as the most prolific scorer at the ground.
South Africa could feel aggrieved at the result. They had led by 92 on the first innings but were forced into making a generous declaration after two days of heavy rain had stalled their bid to build a bigger lead.
With more rain forecast for Friday afternoon, they made their declaration after chalking up 100 runs for the loss of three wickets in the morning session.
Leg-spinner Stuart MacGill captured all three South African wickets to fall in the morning to finish with 3-33 off six overs.
First-innings century-maker Ashwell Prince [ Images ] was caught by a leaping Ponting at short mid-wicket for 18, Jacques Rudolph holed out to Glenn McGrath [ Images ] at mid-on for four and Mark Boucher [ Images ] was stumped by Adam Gilchrist [ Images ] on 11.
South Africa 1st innings 451 for 9 decl (A. Prince 119, J. Kallis 111)
Australia 1st innings 359 (R. Ponting 120, A. Gilchrist 86; A. Nel 4-81)
South Africa 2nd innings (Overnight: 94-3)
G. Smith lbw b McGrath 5
A. de Villiers lbw b Lee 1
H. Gibbs run out 67
J. Kallis not out 50
A. Prince c Ponting b MacGill 18
J. Rudolph c McGrath b MacGill 4
M. Boucher st Gilchrist b MacGill 11
S. Pollock not out 26
Extras (b-3 lb-4 nb-2 w-3) 12
Total (for 6 wickets declared, 42 overs) 194
Fall of wickets: 1-4, 2-6, 3-92, 4-123, 5-129, 6-152
Did not bat: C. Langeveldt, A. Nel, J. Botha
G. McGrath 15 - 2 - 61 - 1 (nb-1)
B. Lee 10 - 3 - 48 - 1 (nb-1)
S. Warne 11 - 1 - 45 - 0 (w-3)
S. MacGill 6 - 1 - 33 - 3
Australia 2nd innings (Target: 287 runs)
J. Langer b Langeveldt 20
M. Hayden c Smith b Botha 90
R. Ponting not out 143
B. Hodge not out 27
Extras (lb-1 nb-4 w-3) 8
Total (for 2 wickets, 60.3 overs) 288
Fall of wickets: 1-30, 2-212
To bat: M. Hussey, A. Symonds, A. Gilchrist, S. Warne, B. Lee, S. MacGill, G. McGrath
S. Pollock 14 - 2 - 55 - 0 (nb-2 w-1)
C. Langeveldt 14 - 1 - 52 - 1 (nb-2)
A. Nel 7 - 0 - 46 - 0
J. Botha 12.3 - 0 - 77 - 1 (w-1)
J. Kallis 2 - 0 - 8 - 0
J. Rudolph 11 - 0 - 49 - 0 (w-1)
Result: Australia won by 8 wickets