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.
But allrounder Jacques Kallis felt there was still plenty of time left, with two extended days' play, and enough moisture in the wicket to ensure a result was highly possible.
"It has quickened up a bit. It is a good Test wicket. There is a bit in it for the fast bowlers when they get the ball in the right area," Kallis said on Sunday night.
"Tomorrow morning is a key period.
"I think we have to give ourselves an opportunity, the game is far from dead."
Kallis admitted Clarke's early wicket would be an important domino to fall.
"That's massive, any wickets we can get tomorrow morning will put them right on the back foot," he said.
"Obviously he's a world-class player and he's shown that, he's a vital wicket for us but we (also) need to pick up a few more."