South Africa have targeted the wicket of Australian skipper Michael Clarke early on day four as key to their hopes of a first Test victory at the Gabba.
Australia resume their first innings at 3-111 on Monday morning with Clarke unbeaten on 34 and opener Ed Cowan not out 49.
The home side remain 139 runs away from the follow-on mark after the Proteas made 450 on batting first on the slow green Gabba wicket.
The tourists' quicks managed to get more assistance out of the Brisbane wicket - reducing Australia to 3-40 at one stage - as it quickened up on day three following a fine Sunday.
South Africa were unlucky not to grab a fourth scalp just before stumps when Cowan was saved by a marginal Morne Morkel no-ball, picked up by the third umpire, after he gloved a catch behind down the leg-side.