South Africa have suffered a body blow ahead of Sunday's World Cup semi-final against Wales with dangerman Cheslin Kolbe ruled out through injury. Kolbe hobbled off after twisting an ankle in the 49-3 pool win against Italy and was in discomfort again in the quarter-finals, when South Africa broke the hearts of host nation Japan. "It's a big blow because everybody knows his quality and the contribution he makes," South Africa coach Rassie Erasmus said, after naming S'Bu Nkosi as his replacement. "But if you look at the previous game, his ankle definitely had an influence on his performance. We don't think a 70 per cent Cheslin is better than a 100 per cent S'Bu." While South Africa, whose only win over Wales in their last six meetings came in the 2015 World Cup quarter-finals, will miss Kolbe's explosiveness, Erasmus was quick to point out that Nkosi was no slouch, with eight tries in 10 Tests to his name. "Cheslin's top-end speed and agility – he's one of the best in the world," he said. "But we have full confidence in S'Bu and he certainly deserves his chance." Nkosi, set to make his third appearance of the World Cup, is South Africa's only change and joins Makazole Mapimpi, the tournament's joint top try-scorer with five tries, on the other wing. "Having Makazole in the form he's in is fantastic," said Erasmus, who has made the Boks a force again since taking over in 2018. "Obviously in the last four games Wales are 4-0 [on us]. I don't know who's the favourites, but we fully believe we can beat them." Meanwhile, Jake White believes that Wales captain Alun Wyn Jones could be destined to lift the Rugby World Cup. South Africa's 2007 World Cup-winning coach has lavished praise on Jones ahead of the semi-final in Yokohama. Wales reached the semi-finals for a second time in the last three World Cup tournaments after scraping past France 20-19 last weekend. "There are people who are destined to pick up the World Cup," White said. "You look at [Richie] McCaw, [Francois] Pienaar and [John] Eales. "Now you look at Alun Wyn Jones. I really believe he can do it. He is the real deal – a great captain. I don't think people foresaw what he would do for Welsh rugby when he started. "He has become one of the great Welsh players of all time with what he has achieved as a British and Irish Lions captain and a Wales captain. "I would say it is far beyond what even he could have dreamt of. He is the heartbeat of Wales, and if he is there, then Wales have got a chance."