England must pull off yet another second-innings rearguard effort if they are to remain unbeaten in South Africa and score a famous series victory.
As bad light threatened an early close to day three of the final Test at The Wanderers, they were an unenviable 221 runs short of avoiding an innings defeat - on 22 for two.
After South Africa had declared on 423 for seven, the tourists lost Alastair Cook and Jonathan Trott for single-figure scores.
They therefore need to revisit the resilience of Centurion and Newlands, in the first and third Tests of this epic series, to have any chance of keeping South Africa at bay again.
Cook and Trott fell in near mirror image, each to a very good ball - the opener edging Morne Morkel to first slip and Trott playing Dale Steyn to third. South Africa's new-ball pair made life mighty difficult for Andrew Strauss too with some quick and well-directed deliveries on a pitch which has had good carry throughout.
Respite came only when the umpires decided the light had deteriorated sufficiently to take the players off, with 29 overs remaining.
England had earlier struggled to contain their frustrations as Mark Boucher (95) and AB de Villiers kept the hosts in control.
A series of marginal calls went against the tourists, who need to avoid defeat here to cling on for a 1-0 series success.
Boucher and De Villiers shared a damaging sixth-wicket stand of 120 in 29 overs, as South Africa reasserted a dominant position in pursuit of the victory which would mean they share the honours this winter.
With tempers still stirred off the pitch as well as on following third umpire Daryl Harper's controversial decision yesterday to confirm South Africa captain Graeme Smith not out caught behind off Ryan Sidebottom on the way to a century, England again found themselves on the wrong end of several close calls.
Most concerned De Villiers, who twice survived via the decision review system (DRS) when Tony Hill had initially given him out off Graeme Swann - caught at leg slip on 11 and lbw playing no shot on 24.
De Villiers was doubly fortunate with the second too when the ball ricocheted off his pad on to the stumps but without sufficient force to dislodge the bails.
Perhaps the most clear-cut disappointment for England came with De Villiers on 40 of the 58 he eventually made, with Sidebottom again the unlucky bowler when it seemed the batsman might have got an inside edge behind. He was given not out, though - and England had already used up their DRS chances.
De Villiers finally went when he chipped a catch to mid-on off Stuart Broad. But Boucher stayed to pass a personal milestone of 5,000 Test runs, and test England's anger management a little further.
The habitual afternoon storm forced the players off the field. But only five overs were lost either side of an early tea, and Boucher returned under floodlights with debutant Ryan McLaren to take toll of a tiring attack until he holed out in the leg-side deep - yet again from the first ball of a Swann spell - with a sixth Test hundred in his sights.
The second new ball had brought England no further gains, after three early-morning wickets.
The reintroduction of Swann resulted in the day's first major dose of aggravation for the tourists when the off-spinner wanted to review an lbw decision from the first ball of his spell but was not supported by his team-mates.
Replays showed Boucher, on 33, would have been given out by the third umpire; then the same batsman survived another tight lbw four runs later, as England used up their remaining DRS appeal to no avail.
The day had begun encouragingly for Andrew Strauss' team, Broad (three for 83) striking first as Hashim Amla went for the addition of only two runs to his overnight 73 - and then Sidebottom saw off Jacques Kallis.
Both wickets fell on 217, as England threatened to claw back lost ground.
Amla followed some swing from Broad and edged behind, where Matt Prior took a diving one-handed catch in front of first slip in the first full over of a sunny morning.
Kallis followed almost immediately when his attempted hook at Sidebottom took the glove and somehow looped to gully, where James Anderson took another fine catch.
Then England had another breakthrough thanks to Swann's party trick of a wicket with his first ball - JP Duminy's frailty to a well-pitched off-break again exposed as he edged to first slip.