* South Africa in trouble at 77-4
* Tourists need 353 runs for victory
* Hussey scores half-century (Adds quotes, details)
By Ian Ransom
ADELAIDE, Nov 25 (Reuters) - A fired-up Australia attack skittled South Africa's top order late on the fourth day to march to the brink of victory in the second test on Sunday.
Set a mammoth target of 430 for victory, the tourists' chase began disastrously, captain Graeme Smith out for a duck with the sixth ball of the innings and three more wickets tumbling quickly in the afternoon heat at Adelaide Oval.
Wicketkeeper batsman AB de Villiers and Faf du Plessis dug in for more than an hour and a half, but South Africa staggered to 77-4 at the close, 353 runs adrift of their target.
De Villiers was on 12 and Du Plessis on 19, with injured Jacques Kallis the last specialist batsman in the Proteas' dressing room.
South Africa assistant coach Russell Domingo conceded a draw was the best they could hope for.
"Definitely, yeah ... We know that 370 on the last day, four wickets down is probably out of the window," he told reporters.
"The target is far away, but they're still out there.
"There's every possibility that something special could happen, so there's an opportunity for someone to make a major play for his country."
South Africa's hopes may again rest on all-rounder Kallis, who battled a hamstring strain to score a half-century in the first innings and help the tourists avoid the follow-on.
With Smith and number three Hashim Amla out before tea, Jacques Rudolph and opener Alviro Petersen resumed at 40-2 but their partnership lasted only five more runs before spinner Nathan Lyon claimed his second wicket of the innings.
Lyon, who two years ago worked as a groundsman at Adelaide Oval, had Rudolph poke the ball to Ed Cowan, who lunged low and to his left to take a sharp catch at short leg.
Out for three, Rudolph's dismissal was his fourth at the hands of the 25-year-old offspinner from four innings in the series.
Petersen's celebrations for his 32nd birthday were tempered an over later, when he was out for 24, dragging a delivery from fellow birthday boy Peter Siddle onto his stumps to leave his team reeling at 45-4.
"Obviously I guess I can have a bit of a happier one than him tonight, so that's always nice," Siddle told reporters.
Charged with steering South Africa to safety, De Villiers and Du Plessis slowed their scoring to a crawl, with all thought of victory banished.
The pair added only 10 runs in little more than an hour after the last session's drinks break, with every score drawing ironic cheers from sections of the crowd of 16,000.
Any wafer-thin South African hopes may lie with the Australians running out of steam on the final day, with paceman James Pattinson ruled out for the rest of the series with a rib injury and Australia's bowlers forced to shoulder a greater workload.
"Obviously we're in a good position but there's still a lot of work tomorrow morning to be done," said Siddle. "I think if we can stick to the same stuff we did this afternoon we can finish on a good note.
"We'll keep charging in tomorrow, keep banging that wicket and we'll keep having a crack at getting those six wickets."
Pattinson's injury soured a dominant day for the hosts, who resumed on 111-5 and declared after lunch at 267-8 following a feisty ninth-wicket stand of 47 from the bowler and Ben Hilfenhaus.
Smith, who anchored the tourists' first innings with a defiant century, was out for a duck when he sent a thick edge to Ricky Ponting at second slip.
Amla and Petersen added 33 runs for the second wicket before Lyon struck to remove the number three for 17 off 36 balls, caught behind by Australia captain Michael Clarke at slip.
South Africa had torn through Australia's batsmen with five wickets after tea on the day three, but their faint hopes dimmed when Clarke and Hussey dug in for 62 runs in the morning.
Clarke, on a pair of double-centuries, was eventually trapped in front by Dale Steyn for 38, while Hussey added a 54 to his first innings 103 before he skied a simple catch to the paceman just before lunch.
Following the drawn first test in Brisbane, South Africa could lose their top test ranking if they lose the series, with the final match starting in Perth on Saturday.
(Editing by Alastair Himmer)