Cricket: Clarke will go for broke and declare, says du Plessis

Faf du Plessis, who top-scored with 67 in his side's first innings of 287, famously batted for almost eight hours to secure a draw on test debut 16 months ago in Adelaide. Photo / AP

South Africa's saviour in their past two great test escapes is expecting Michael Clarke to err on the side of aggression as he mulls a decisive declaration.

Australia held a 234-run lead over the Proteas at stumps on day three of the series decider in Cape Town, with all 10 wickets in hand and David Warner already 25 from 17 balls.

South Africa have much work to do if they're to avoid a defeat that would result in a first test series loss since March 2009 - also against Australia at home.

Clarke ended the visitors' first innings at 7-494 before the start of play on Monday, and the timing of his next declaration will help decide the series.

Faf du Plessis, who top-scored with 67 in his side's first innings of 287, famously batted for almost eight hours to secure a draw on test debut 16 months ago in Adelaide. He also soaked up 309 balls in another recent dramatic draw, against India in Johannesburg three months ago.

The Proteas were chasing targets of 430 and 458 in those respective matches, and survived around four and a half sessions.

Du Plessis expected his side's doggedness to be at the forefront of Clarke's mind at Newlands overnight, with Australia looking for quick runs to be in a position to declare by lunchtime in Cape Town.

"He'll go more on the aggressive side," du Plessis said of Clarke's declaration. "We've done it a few times ... we will still be comfortable to bat out time. It's a tricky one for them ... if you bat for too long you take time out of the game and if you bat for a short period of time, you give us a chance."

Mitchell Johnson and Ryan Harris bowled magnificently as the world's No 1 test side fluffed their lines after Clarke's masterful knock of 161 not out. Johnson (4-42 from 19 overs) dismissed Alviro Petersen (53), in-form AB de Villiers (14), du Plessis and hamstrung Dale Steyn (28) to overtake Jason Gillespie to be sixth on Australia's all-time test wicket-takers.