South Africa standoff Handre Pollard believes his team's backs have the pace and skill to trouble Wales in Sunday's Rugby World Cup semifinal — if they can get the ball off their forward teammates for long enough.

South Africa faces Wales at International Stadium Yokohama for a place in the World Cup final, with the Springboks having made it to the last four thanks in large part to the power of their formidable pack.

Another bruising forward effort in last Sunday's 26-3 quarterfinal win over Japan meant South Africa's backs were reduced to virtual observers for large parts of the game, but Pollard is happy to see more of the same on Sunday if it takes his team past Wales and into a first World Cup final since 2007.

"We've got that threat loaded, but if your boys are mauling and handling the set piece like our boys are at the moment, you're not going to stop them," Pollard said Friday. "You're not going to fix something that's not broken or change anything.

"It's no secret, the set-piece battle coming on Sunday. I'm sure it will be tougher handling it this week compared to last week. But as a flyhalf, you just let the boys go. Just keep them going forward. It's my responsibility to keep our big boys running forward for the majority of the game."

South Africa head coach Rassie Erasmus has made one change to his starting lineup for Sunday's game, with winger S'Busiso Nkosi coming in to replace the injured Cheslin Kolbe.

Kolbe has been one of the stars of the World Cup with his fast, elusive running, but he has been outshone in the scoring stakes by his teammate on the opposite wing, Makazole Mapimpi.

Mapimpi, who only made his Springboks debut in June last year, shares the lead as the tournament's top try-scorer on five, along with Japan's Kotaro Matsushima and Wales' Josh Adams. South Africa assistant coach Mzwandile Stick has been impressed by the 29-year-old Mapimpi's performances.

"It's a very special story to tell about Makazole," said Stick. "Normally as a youngster he would spend about 10 kilometers a day walking to school. In rural areas, when you kick a rugby ball, the coach will take you off the field. You're not allowed to. You're supposed to run the ball and catch, that's all.

"So he was never exposed to that sort of game where there's kicking and aerial skills and so on. He was always a player who was very fit, very disciplined, dedicated to what he wants to achieve. So when we invited him into our camp last year, we knew what we were dealing with.

"He has developed as a player. It's a very nice story to tell to youngsters that, irrespective of your background, if you work hard, when your opportunity comes you need to be ready. I'm happy to see where Makazole is at the moment."

Another player who has caught the eye during South Africa's World Cup campaign is scrumhalf Faf de Klerk, who was named man of the match and scored a try in the quarterfinal win over Japan.

De Klerk's tenacious attitude and accurate passing have made Pollard's job significantly easier, and the standoff has nothing but praise for his halfback partner.

"I think we've grown a lot the last couple of years, playing together," Pollard said. "We've really jelled together nicely. He's an unbelievable rugby player. I've got a lot of respect for him, on and off the field. He takes a lot of criticism in the media, but he just does what we believe in and does it unbelievably well. I'm sure he'll be brilliant again on Sunday."

Wales will be without fullback Liam Williams for the game, after the 28-year-old sustained an ankle injury that ended his involvement in the World Cup.

Williams will be replaced by Leigh Halfpenny, who also played in Wales' semifinal defeat to France at the 2011 World Cup, and Pollard believes the change does little to weaken the Welsh lineup.

"(Williams) has been playing some great rugby but I think you get the class of Leigh Halfpenny coming in," Pollard said. "There are no worries for them in that position. It doesn't change our plan. I don't think their plan will change dramatically. We'll still just prepare the way we did.

"He's a world-class goalkicker, we all know that, that's no secret. It's on the day. We all know it's probably going to come down to a kick or a drop goal. It's semifinal rugby, so you've got to try your best to be on target every kick you kick. And if it's not to be, it's not to be. But I'm sure it's going to come down to a kick."