West Indies took a commanding 359-run lead over South Africa on Friday despite a late collapse on the third day of the first Test.
At the close, West Indies were 146-8 in their second innings after dismissing South Africa for 195 with medium-pacer Dwayne Bravo taking four for 24. West Indies made 408 in their first innings.
AB de Villiers top-scored for South Africa with a gritty 59 in more than three hours in which he faced 127 balls and struck nine fours.
South Africa slipped to 129-6 with the 16th ball of the day's play, when Mark Boucher (20) hooked into the hands of Daren Powell at fine-leg to secure fast bowler Jerome Taylor's third wicket.
De Villiers and Paul Harris stood firm for 18.1 overs in a stand of 43.
The partnership was ended in the fifth over before lunch when De Villiers was squared up by a delivery from Bravo which went on to uproot his off-stump.
Four overs later Harris, who faced 67 balls for his nine, scooped a drive off Bravo and was caught by Taylor at mid-off.
Bravo had Andre Nel caught by Daren Ganga at mid-on for 16 with the third ball after lunch, and in Bravo's next over Dale Steyn hooked a catch to Powell at fine leg to go for seven.
Chris Gayle hit five fours and a six in his 29 before edging a delivery that fast bowler Makhaya Ntini angled across him to wicketkeeper Boucher.
Pace bowler Jacques Kallis struck with his first delivery of the innings when he had Runako Morton trapped in front for five in the sixth over before tea.
Ganga and Samuels added 65 for the third wicket before Ganga, who scored 45, tried to take a single to left-arm spinner Harris and was run out by Herschelle Gibbs's direct hit from point onto the stumps at the non-striker's end.
Samuels was out 10 balls later when he chopped a delivery from Steyn on to his stumps and was bowled for 40.
Harris removed Bravo for 10 after a drive that was heaved down Gibbs' throat at long on, and three balls late Steyn had first innings century maker Shivnarine Chanderpaul caught by Kallis at second slip for eight.
Harris trapped Daren Sammy leg-before for three before Denesh Ramdin (0) gloved a bouncer from Steyn to Gibbs in the gully.
Scorecard
West Indies first innings 408
South Africa first innings (122-5 overnight)
G. Smith lbw b Taylor 28
H. Gibbs c Ramdin b Powell 0
H. Amla b Powell 29
J. Kallis c Bravo b Taylor 0
A. Prince c Morton b Powell 20
A. de Villiers b Bravo 59
M. Boucher c Powell b Taylor 20
P. Harris c Taylor b Bravo 9
A. Nel c Ganga b Bravo 16
D. Steyn c Powell b Bravo 7
M. Ntini not out 0
Extras (b-4 lb-1 nb-1 w-1) 7
Total (all out, 62.1 overs) 195
Fall of wickets: 1-1, 2-45, 3-53, 4-63, 5-96, 6-129, 7-172, 8-181, 9-194, 10-195
Bowling: Powell 17-4-58-3 (w-1), Edwards 15-3-56-0 (nb-1), Taylor 13-4-46-3, Bravo 13.1-3-24-4, Sammy 4-2-6-0.
