Click here for scorecard

Martyn steered Australia to a total of 554 with a magnificent 117 after featuring in partnerships with Brett Lee, Shane Warne and Stuart MacGill - all better known for their exploits with the ball rather than the bat.

"It's great for me to get a hundred here, I haven't got one in Sydney before, but I didn't do it by myself," Martyn said.

"Our goal is to get partnerships right down. These blokes work hard on their batting and that's why we can turn our 300s and 350s into 500s."

Martyn made good use of the reverse sweep, he said because of South Africa's bowling to the leg side.

"It was frustrating the way they were bowling, so I was just trying to put it back on them and change the field," he said.

"I was just looking for a boundary shot, without too much danger, and it worked pretty well."

Spin trouble

South Africa's misery was compounded when fast bowler Glenn McGrath and leg-spinner MacGill took two wickets each in the final session to leave the visitors 93 for four at stumps, still 262 short of the follow-on target.

"We've done the first part now we've got to try and bowl them out twice," said Martyn.

"The last hour was a good session for us; to get four wickets was a bonus.

"We're in a good situation; they've got to chase 550 so we can attack for as long as we like."

Despite being on the brink of a 3-0 series sweep, Martyn said the South Africans had proven themselves as difficult opponents and had never thrown in the towel at any stage.

"They've been trying hard, they've put in the whole game," he said.

"Last night was good for them when they got those late wickets but we batted well today. If they got a few early wickets it might have been a bit different.

"They're tired after fielding for 10 hours, though, and now they've got to come out and bat pretty well and we've got two great spinners who are turning the ball a long way."