Langer receives assistance after being hit on the helmet

South Africa battered and bruised Australia on the second day of the final Test in Johannesburg.

Justin Langer had to retire hurt in his 100th Test, hit on the helmet with the first delivery of the innings, bowled by Makhaya Ntini, who took 5-80.

Australia struggled with the bat and at the close were 246-7, Mike Hussey rescuing them with 73.

Earlier South Africa had been dismissed for 303 with Ashwell Prince hitting 93 and Nicky Boje adding 43 off 44 balls.

Australia were ruffled by Langer's misfortune as he had to be assisted from the field looking groggy and with spots of blood on his shirt.

News story: Langer injured in 100th Test

Fellow opener Matthew Hayden was soon back in the pavilion after edging to Herschelle Gibbs, who took a great catch in the slips, for three.

Damien Martyn seemed in a hurry, smashing Ntini for a six and a four in his first over but he only lasted 21 balls and scored an equal amount of runs as Ntini got his revenge.

Captain Ricky Ponting, who hit two centuries in the last Test, was dismissed for 34 as he pushed at a Ntini delivery and was caught by AB de Villier's at third slip.

Australia had scored at a quick rate but Andrew Symonds looked uncomfortable facing a relatively new ball and was out lbw.

Ntini celebrates the 11th five-wicket haul of his Test career

Andre Nel then got in on the wickets, getting rid of Adam Gilchrist, who mis-timed a pull shot over mid-wicket and was caught by Jacques Rudolph for 12 to leave the tourists on 106-5.

Australia recovered after tea with Hussey and Shane Warne adding 68 runs for the sixth wicket before Warne hooked one too may times and was caught by Shaun Pollock for 36, to give Ntini his 11th five-for.

In fading light, Hussey was hoodwinked by spinner Boje and was trapped lbw. Brett Lee was putting up a fight and at the close he was unbeaten on 42 with Mike Kasprowicz yet to score.

"It was a pretty tough battle early when the ball was hard, the movement was just so aggressive," said Hussey.

"There was massive movement so it was pretty daunting, you never feel comfortable on a wicket like that.

"I was desperate to be there at the end of the day so I was disappointed to get out."

The day had started with South Africa on 238-6 but they lost Pollock early on for eight when Ponting snapped him up at slip.

Prince was 79 not out overnight and looked set for his fourth Test ton but Lee ruffled his feathers with the new ball and got one to move away off the seam, which he edged to Langer at slip.

That brought Nel to the crease but those expecting fireworks from the tough man of Test cricket were disappointed as he fell for an eighth-ball duck, skying a catch to Martyn at mid-on.

Boje got South Africa past the 300 mark but his attacking innings was soon over when Mike Kasprowicz angled a delivery in and Boje pushed it to Langer at slip.