Australia are staring down the barrel in Perth after centuries from Hashim Amla and AB de Villiers powered South Africa beyond the 500-mark and eventually set the hosts an unfeasible victory target of 632 to win the decisive Test.
The Proteas decided to continue with their foot-down batting, with Amla and de Villiers piling up the runs and skipper Graeme Smith in no mood to declare, instead looking to bat Australia into submission.
The hosts did manage to bowl them out late on what was still somehow only the third day of the third and final Test, but their 569 gave them a whopping lead of 632 and put them within touching distance of a series win.
The Aussies still have two days to try and record what would be a record victory, but far more likely they will be trying to dig in and survive at the WACA and hope that any predicted rain on the final day comes early.
Amla started the day on 99 and quickly moved into three figures, but fell just short of a deserved double century as he was out for 196, while de Villiers grabbed a much-needed ton with a brilliant 169 from just 184 balls.
South Africa had rattled along at more than five runs an over which meant Smith did not have to think about the declaration too much with still just over two days remaining.
Mitchell Starc and Mitchell Johnson took all of the South Africa wickets, with Starc taking his first five-wicket haul in Test cricket, although he will hardly be jumping for joy with his figures of 6-154.
Michael Clarke's side faced a nervy final hour at the crease, but their battle for survival did start well as openers Ed Cowan and David Warner survived 13 overs before stumps were drawn for the day.
Wickets had been tumbling all over the place in the first couple of days, but after a brutal onslaught late on the second day, a more thoughtful Amla emerged with South Africa in a comfortable lead.
More considered shots flowed from the right-hander as he picked up an 18th Test century, and de Villiers came in to join him after Jacques Kallis went for 37 but initially struggled to settle.
The lunch break saw a change though and he produced more of his attacking prowess, including three consecutive reverse sweeps to bring up his first century since taking over as Test wicket-keeper.
Amla missing out on his double hundred and Dean Elgar getting a pair on his Test debut were the only two minor downsides on an otherwise superb day for the number one Test team.
Smith's side look like retaining that title at the end of 2012 unless Australia somehow find a way out of such a sticky situation, with a mammoth target and two full days of South Africa bowling ahead of them.