Port of Spain - Morne Morkel ran through the top order of the West Indies' batting in a decisive opening spell before lunch to put South Africa in control of the opening Test on Saturday.
The lanky fast bowler captured three wickets for seven runs from seven overs, as West Indies, replying to the South Africans' first innings total of 352, reached 65 for three at the interval on the third day.
Extracting some bounce, if not movement from the hard, true Queen's Park Oval pitch, Morkel ripped out makeshift opener Travis Dowlin, left-hander Brendan Nash, and West Indies captain Chris Gayle in successive overs to leave the home team on 12 for three.
But the Proteas failed to make further headway, with Narsingh Deonarine not out on 27 and Shivnarine Chanderpaul not out on 24 busily trying to restore stability to the West Indies batting with an unbroken stand of 53.
Morkel made the breakthrough, when Dowlin edged and was caught at first slip for four playing defensively on the back-foot to rising ball.
In his next over, Morkel benefitted from a questionable decision from video umpire Simon Taufel of Australia that removed Nash for one.
The fast bowler delivered a short, rising ball from which the Australia-born left-handed batsman, tried desperately to sway out of the line.
The ball looked like it clipped the glove through to 'keeper Mark Boucher, and the Proteas appealed for a caught behind decision, but standing umpire Steve Davis, also from Australia, ruled "not-out.
South Africa referred the decision to Taufel, and it was overturned after a series of replays, although there was not enough conclusive evidence to overturn the original decision.
Further video replays seemed to suggest that the ball from Morkel brushed the sleeve of Nash's jersey.
Morkel then struck a vital blow, when Gayle essayed an ill-advised pull at a short ball of no great merit, and was bowled for six, when he dragged the first ball following a drinks break into his stumps.
The two sides also play Tests in St. Kitts (June 18-22) and Barbados (June 26-30).
South Africa have dominated West Indies in Tests since their re-entry into international cricket following international isolation.
They have won 14, and lost three of the 22 matches between the two sides, and two of the wins came at Port of Spain in 2001 and 2005 in the two Tests the sides have played here.