South African captain Smith and his Australian counterpart Clarke feel the heat before decisive 3rd Test

Cape Town: Captains Graeme Smith and Michael Clarke will be under greater than usual pressure when South Africa and Australia clash in the series-deciding third Test from Saturday.

Apart from the normal challenge of trying to win a showdown at Newlands between two of cricket's top teams, both skippers will be seeking to end a run of poor personal form with the bat.

And both will be facing bowlers who have been a nemesis during their careers.

Smith has had scores of 10, 4, 9 and 14 in the first two Tests, while Clarke has made 23, 17 not out, 19 and 1.

Smith has been out three times to left-arm fast bowler Mitchell Johnson, who has now dismissed him eight times in 10 Tests.

No bowler has claimed his wicket more often in Tests, although Chris Martin of New Zealand also got him out eight times in 11 matches.

Clarke has fallen twice to Dale Steyn, taking his number of dismissals against South Africa's fast bowling kingpin to nine in 13 Tests, equal with Englishmen James Anderson (23 Tests) and Stuart Broad (17 Tests).

Both captains have rejected concerns about their form.

Smith points out that he scored a double century against Pakistan five Tests ago and that he has had success as well as failures against Johnson.

"I've faced Mitchell a lot of times -- times where he's had the better of me and times where I have had the better of him," Smith said before South Africa squared the series by winning the second Test in Port Elizabeth.