Rugby World Cup 2019: South Africa wing Cheslin Kolbe out of semi-final against Wales

South Africa has suffered a big blow ahead of their Rugby World Cup semi-final against Wales, with winger Cheslin Kolbe - one of the tournament's standout players - ruled out through injury.

Kolbe missed South Africa's pool match against Canada with the ankle problem and had to leave the field in the latter stages of last week's quarter-final against Japan.

He missed training on Tuesday and will be replaced for Sunday's match in Yokohama by Sbu Nkosi in the only change to the team that beat the hosts last week.

"It is a big blow, everybody knows the quality of his play and the contribution he's made," said Springbok coach Rassie Erasmus.

"But if you look at his last game, his ankle definitely affected his performance and we just feel a fully fit Sbu would be a better option than a 70-percent Cheslin."

Nkosi has scored eight tries in 10 tests since making his international debut last year - including two in his first test against England - and Erasmus said he would bring his own special qualities to the team.

"Cheslin, in terms of top-end speed and territory [gained], is one of the best players in the world... so that's definitely something we will miss," Erasmus said.

"But aerially, Sbu is right up there with what most of the best players in the world can do.

"And powerwise Sbu brings something special to the party."

Erasmus said he had considered changing the balance of his bench, but decided to stick with six forwards and two backs in the replacements to allow him to refresh the pack.

"It's been working for us and not just working for us in terms of the thing everybody sees - the physicality, mauling, scrumming and gainline and those kind of things," he said.

"Having a fresh tight five on the field for 80 minutes helps you on attack and defence - especially on defence - shutting holes, which we'll really need against a very experienced back line."

Six Nations champions Wales have beaten South Africa in their past four meetings, but Erasmus said only the last two of those had come on his watch and he does not think it holds much relevance for Sunday.

"This is the game that will tell and will count," he said.

South Africa: Willie le Roux, S'Busiso Nkosi, Lukhanyo Am, Damian de Allende, Makazole Mapimpi, Handre Pollard, Faf de Klerk, Duane Vermeulen, Pieter-Steph du Toit, Siya Kolisi (capt), Lood de Jager, Eben Etzebeth, Frans Malherbe, Bongi Mbonambi, Tendai Mtawarira.

Reserves: Malcolm Marx, Steven Kitshoff, Vincent Koch, RG Snyman, Franco Mostert, Francois Louw, Herschel Jantjies, Frans Steyn.

Join us at 10pm Sunday for live updates of the South Africa v Wales Rugby World Cup semi-final.