Australia edge tense first day
Australia dismissed South Africa for 225 to seize the initiative on day one of the decisive third Test at the WACA.
Faf Du Plessis, who batted throughout the entire final day to keep the series level in Adelaide, defied Australia for a second Test match running with an unbeaten 78 before South Africa's seamers struck twice before stumps to raise spirits.
Despite losing Ed Cowan (0) and Shane Watson (10) late on, Australia ended day one the happier side after Michael Clarke lost the toss and was forced to bowl first with a makeshift pace attack.
Recalled trio Watson, Mitchell Starc and Mitchell Johnson and debutant John Hastings responded to the challenge, though, helping reduce South Africa to 75-6 inside the opening 31 overs.
Watson, back from a calf injury, claimed the breakthrough when luring South Africa skipper Graeme Smith (16) into a loose prod outside off stump - opposite number Clarke pouching well at first slip.
After an unsuccessful opening spell, left-arm seamer Starc then returned and removed Alviro Petersen (30) and Jacques Kallis (2) in identical fashion with inswinging, full deliveries which crashed into off stump on the stroke of lunch.
The wickets continued to tumble after the lunch break as Hashim Amla (11), AB De Villiers (4) and debutant Dean Elgar (0) all came and went to leave South Africa in dire straights on 75-6.
But Du Plessis shared half-century stands with Robin Petersen (31) and Vernon Philander (30) to take South Africa past 200 and Steyn and Philander removed Cowan and Watson respectively to see Australia end the day on 33-2.
Amla was sent on his way just after lunch when David Warner swooped athletically at cover and threw down the stumps with the right-hander marginally short of his ground.
De Villiers then became Hastings' maiden Test scalp when another edge was safely pouched by Clarke at slip and Johnson ensured Elgar's first knock in Test cricket was a brief one when he top-edged an attempted pull straight up, where Matthew Wade settled under the catch.
South Africa desperately needed a partnership and Du Plessis and recalled all-rounder Petersen began repairing the damage with a half-century stand before Lyon claimed the first of three lower-order wickets.
When Petersen had edged his attempted cut off the spinner through to Wade, Du Plessis and fit-again all-rounder Philander came together with Australia still in command with the scorecard reading 132-7.
The situation was Du Plessis' cue to up the ante and he went past 50 for the third time in three Test innings', while Philander looked assured at the other end.
The pair had taken the score along to 196 before Philander skied Lyon straight up and Mike Hussey held his nerve under the high ball to claim a spectacular catch.
Du Plessis, who struck 12 boundaries in his 142-ball knock, took South Africa past 200 before Morne Morkel's late fun was ended by Lyon, who finished with 3-41 from 12 overs.
That left Australia with an awkward 40-minute spell to negotiate before the close and they failed to see it out unscathed as Dale Steyn and Philander both struck.
Steyn snared Cowan for a golden duck after another sharp slip catch from Kallis before Philander pinned Watson lbw via the use of DRS. Warner (12no) and nightwatchman Lyon (7no) will return to the middle on day two.