Fast bowler Dale Steyn grabbed 5-29 and teammate Morne Morkel took 4-19 as South Africa blew away West Indies for 102 and took a firm grip of the opening Test on day three Saturday. South Africa, after sealing a first-innings lead of 250, stretched its advantage to 405 as it closed at 155-2. Captain Graeme Smith hit an unbeaten 79 and Jacques Kallis, 40 not out. Earlier, Morkel did the early damage before Steyn ripped apart the middle and late order on his way to crossing 200 Test wickets. Only three West Indians reached double figures with Narsingh Deonarine topscoring with 29. Shivnarine Chanderpaul contributed 26 and Denesh Ramdin an unbeaten 25. West Indies began the day replying to South Africa's first innings total of 352 and was soon deep in trouble. Morkel claimed Travis Dowlin, Brendan Nash and captain Chris Gayle as the host slumped to 12-3 inside the first hour. Dowlin (4) fell first as he deflected a catch to first slip where Smith hauled in a low catch. Next over, left-hander Nash (1) was controversially ruled caught behind after Smith successfully challenged umpire Steve Davis' original not out decision. Gayle (6) soon followed as he dragged an ugly pull back into his stumps to spark more celebrations for the South Africans. The experienced Chanderpaul and fellow left-hander Deonarine stalled the partying with a fourth-wicket stand of 59 either side of lunch. But the innings was derailed in the second session once Chanderpaul fended a Steyn bouncer to wicketkeeper Mark Boucher. The innings subsided dramatically with six wickets tumbling for four runs in 28 deliveries. Dwayne Bravo (1) also fended to Boucher to give Morkel his fourth wicket. Steyn then took over with some quality, fast swing bowling. Deonarine misjudged an inswinger and lost his off stump as he played no stroke. The tail was no match for Steyn as Shane Shillingford was leg before first ball and Suleiman Benn (0) and Rampaul (0) had their stumps rattled. Steyn, in his 39th Test, reached 200 career wickets with Benn's.