Australia are 3-142 at stumps after 37 overs with former captain Ponting 54 not out and his successor Michael Clarke new at the crease and unbeaten on 1.
South Africa were eventually bowled out for 339 in their second dig shortly after lunch on day four, setting Australia a record victory target of 310 to square the series.
Usman Khawaja (65) made the highest score in his four-Test career and Ponting crafted his first half-century in 12 months in a crucial partnership of 122.
It came after Vernon Philander (2-31) knocked over openers Shane Watson (0) and Phil Hughes (11) early to leave Australia reeling at 2-19.
Ponting is still a long way from his first century since January 2010, but so far he's playing like a man on a mission.
Plenty has been written about how the Tasmanian's eye, timing and confidence isn't what it was.
This is all true, but Ponting showed the fighting spirit which has defined his career is still burning away within.
Under intense pressure to hold his place in the side for the start of the Australian summer, Ponting needed a big score to keep the wolves at bay.
The end may still be near, but Ponting gave a timely reminder of his place amongst the greatest batsmen of all time.
Khawaja was also in need of runs after a career so far comprised by solid starts.
The 24-year-old played superbly, hitting eight fours and a six before being undone by spinner Imran Tahir (1-23).
It was a telling blow in the final minutes before bad light stopped play early for the fourth consecutive day.
Only four teams have ever won in Johannesburg batting last and the highest successful fourth-innings run chase was 294 set by Australia in 2006.
Earlier on an eventful day, debutant Pat Cummins became the youngest Australian cricketer to take five wickets in an international innings.
Cummins' efforts might not be enough to win the Test, but at just 18 years and 196 days, he's announced himself as a star prospect and future leader of the Australian attack.
The NSW Blue Mountains product's 6-79 made him the second youngest player ever to take six wickets in an innings, behind Bangladeshi Enamul Haque Jnr.
He also became the fifth youngest in Test history to take five wickets in an innings - ahead of Shahid Afridi and Wasim Akram.
Cummins took two wickets in the first two balls after lunch, and finished the match with 7-117 from 44 overs.
With Watson unable to bowl, Ryan Harris injured and Mitchell Johnson (1-101) and Peter Siddle (0-71) struggling for impact, Cummins virtually carried Australia's attack in the third innings along with Nathan Lyon (2-57).
In the first session, Hashim Amla made 105 for South Africa.