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Australia's Mitchell Johnson was shocked after producing one of the greatest spells in cricket history, taking five wickets for two runs in 21 balls to reduce South Africa to 243 for eight on day two of the first test.
Johnson has career-best figures of 7-42 from 18 overs, his second five-wicket haul in his 16th test, to put Australia in a strong position after the home side were bowled out for 375 on Thursday at the WACA Ground.
South Africa had been cruising at 234 for three late in the day's play before losing five wickets for seven runs.
Left-armer Johnson landed five hammer blows in 33 minutes.
AB De Villiers (63), Jacques Kallis (63) and debutant JP Duminy (1) were all caught behind and Morne Morkel (1) and spinner Paul Harris (0) were both caught by Jason Krejza.
"I'm in a bit of shock, to be quite honest," Johnson said.
"The reception was pretty great, just to hear the crowd as you walk back to fine leg. It was a great feeling.
"At one stage I was still called a Queenslander until late on this arvo," added Johnson, who has switched state teams to WA for this summer to be with his Perth-based girlfriend.
Johnson had dismissed opener Neil McKenzie for two before lunch, caught at mid-off after a bizarre attempt to play a pull shot.
Captain Graeme Smith and Hashim Amla shared a 90-run stand for the second wicket as the No 2-ranked Proteas began to lay the platform for a big total.
But spinner Krejza put the tourists on the back foot when right-hander Amla was bowled between bat and pad in a classic off-spinner's dismissal at 106 for two.
Smith, who was treated for an elbow injury during his 2-1/2-hour innings, was out four runs later for 48 when he dragged a full-length ball from Johnson onto leg stump.
Krejza (30 not out) and No 11 Peter Siddle (23) frustrated the tourists for 40 minutes in a 34-run partnership.
Makhaya Ntini led the Proteas in the field with his 4-72 from 19.5 overs.
Australia vice-captain Michael Clarke injured his right thumb while fielding in slips and went to hospital for an x-ray but later returned to field again in the post-lunch session.
Johnson added: "It all just seemed to happen.
"This morning I was a bit nervous and started a bit slowly but as the day went on it all came together.
"It happened pretty quickly for me and it feels pretty good.
"As a team we bowled pretty well. We had a period after lunch when we let a few runs go but then we stuck to our guns and personally it felt really good."
- AAP