ADELAIDE, Nov 24 (Reuters) - Australia's bowlers landed a devastating blow early on day three of the second test, taking five wickets to leave South Africa reeling at 273-7 at lunch on Saturday.
Pace bowler Peter Siddle removed century-maker Graeme Smith and AB de Villiers in a fiery spell of 2-7, after spinner Nathan Lyon had Jacques Rudolph caught early in the session at Adelaide Oval.
Ben Hilfenhaus later took the new ball and had Dale Steyn out for one and Rory Kleinveldt for a duck.
Debutant Faf du Plessis was on 26, with the injured Jacques Kallis surviving on 11 after having his hamstring strain painfully tested by venomous short-pitched bowling by Siddle.
South Africa still trail Australia's mammoth first innings total of 550 by 277 runs, with the heat rising at Adelaide Oval.
Proteas captain Smith and Rudolph resumed on 217-2 but were soon on the back foot as Siddle steamed in and gleaned maximum impact from the old ball on a flat wicket.
The red-headed Victorian knocked Smith on the glove early with the deflection sailing just wide of wicketkeeper Matthew Wade to the boundary.
It was offspinner Lyon who sparked the rout, however, as he coaxed Rudolph into an ill-conceived drive that went straight to Rob Quiney at cover.
With Rudolph out for 29, the third-wicket partnership ended at 64 runs, but Smith was unable to dig in further as minutes later Siddle had him caught behind by Wade for 122.
Smith on Friday had survived a blown stumping chance and a caught behind decision that was overturned on review, but his luck ran out with his referral turned down and he trudged off the ground fuming.
Siddle then removed AB de Villiers for one, trapping the wicketkeeper in front, the decision upheld by video review after another referral.
Michael Clarke took the new ball as soon as it came available and threw it to Hilfenhaus who paid his captain back by capturing Steyn and Kleinveldt in quick succession.
Pitching the ball short of a length and swinging it away, Hilfenhaus found Steyn's outside edge and Ricky Ponting completed a comfortable catch at second slip.
Five deliveries later, the Tasmanian workhorse knocked over Kleinveldt's off-stump as the rookie pace bowler attempted to smash the ball over midwicket.
With South Africa flailing at 250-7, having lost five wickets for only 17 runs, the injured Kallis hobbled to the crease and lofted a boundary to long on, but was soon feeling the pain.
After ducking a Siddle bouncer, the 37-year-old grimaced as he grabbed his right thigh and hopped away from the crease.
The merciless Siddle duly tested Kallis's fitness again and again, peppering the all-rounder with short-pitched deliveries, including a deliberate no-ball before lunch to reap maximum punishment.
Australia pace bowler James Pattinson left the field before the end of the session to have treatment for a side strain. (Editing by Greg Stutchbury)