Cricket: Clarke leads way with 27th test ton

Heavy rain has halted Australia's momentum in the Test series decider, but centurion Michael Clarke doesn't expect it will cost his side victory in Cape Town.

Clarke reached 161 not out when showers forced the players off the field at 2.14pm local time on day two, with the visitors in complete control at 7-494.

The heavy covers proved difficult to batten down at windswept Newlands, but once the truck tyres were in place they remained there until play was abandoned at 4.20pm.

It is near impossible to imagine the Proteas battling back to level footing, especially with Dale Steyn nursing a hamstring strain and in doubt to bowl again in the match.

But the odds of the hosts salvaging a draw and avoiding a first Test series loss since 2009 have shortened.

Clarke planned to assess conditions on Monday morning before deciding whether to declare, but was upbeat there would be a result regardless.

"The advantage now is we start at 10am every day, so we'll still get some overs back," said Clarke, who is still making opposition skipper Graeme Smith pay for dropping him on 26.

"The forecast is pretty good for the next three days.

"If we think declaring overnight is the best way (to win) then it doesn't bother me."

Clarke has had Test innings of more runs, but arguably none of greater importance and never under greater duress.

The stoic skipper donned a bandaged arm and borrowed arm guard when he resumed on 92 on Sunday, still in pain from a series of blows that Morne Morkel struck in a brutal short-pitched assault on day one.

"Plenty of treatment, plenty of ice," Clarke said of how physio Alex Kountouris and doctor Peter Brukner helped him recover.

"It was a long night, a longer morning to be honest.

"Without their help, no way would I have got on the park today."

Clarke brought up his 27th Test ton with a cover drive for four off Vernon Philander, having faced 25 balls on 99.

During that period Steve Smith (84) was nearly run out and Clarke left a series of deliveries that went within millimetres of hitting the stumps.

Philander, Morkel and Kyle Abbott have bowled a combined 78.3 overs in the absence of Steyn.

None of them trigger trepidation like Steyn, and none have made a breakthrough since Steyn went off the park in the 40th over on Saturday.

Abbott dismissed suggestions victory was impossible.

"There's a series up for grabs and I still think there's plenty of time left in the game to get a result," he said.

"We have to bat as well as they have.

"We need to push the game forward, keep positive. As soon as we start thinking of a draw or any negative thoughts like that come in, that's when you come unstuck."

Philander's figures of 1-116 are his most expensive at Test level, while part-timer JP Duminy has career-best figures of 4-73.

Duminy captured the wickets of Shane Watson (40), Brad Haddin (13) and Mitchell Johnson (duck) in the hour that followed lunch on Sunday.

- AAP