Gros Islet (St Lucia), June 21 : A 70-run, eighth-wicket partnership between Rassie van der Dussen and Kagiso Rabada put South Africa in the driver's seat on the third day of the second and final Test against the West Indies at the Daren Sammy Cricket Ground here. Van der Dussen scored his sixth Test half-century -- returning an unbeaten 75 (5x4s, 1x6) -- after a batting collapse, while Rabada contributed 40 (5x4s, 1x6) to guide the visitors to 174 in the second innings, setting the home team a 324-run target to win. At the close on Sunday, West Indies were 15 without loss, still 309 runs adrift. The Proteas have taken an unassailable 1-0 lead in the two-Test series by winning the opening Test at the same venue. After the first session was lost due to a wet outfield caused by overnight rain, the Proteas lost the top and middle orders in quick succession, struggling at 54/6 when Keshav Maharaj and Van der Dussen took control of the situation and added 19 runs before the former departed. The 26-year-old Rabada, who got a career-best score and had a strike rate of 83.33, took some pressure off Van der Dussen as the duo took South Africa 174 all out, setting the hosts an imposing target of 324 to win. Brief scores: South Africa 298 & 174 (R van der Dussen 75 not out, K Rabada 40; K Roach 4/52, Kyle Mayers 3/24). West Indies 149 & 15 for no loss. /IANS