Johannesburg - The racial transformation of the Springboks roared into overdrive when Siya Kolisi skippered a team including six black players to a Rugby World Cup final triumph over England.

South Africa outplayed the pre-match favourites 32-12 in Japan on Saturday, winning by a much wider margin that even their most partisan supporters anticipated.

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And for those who believed black players would strengthen a national team once reserved for whites, it was a day of vindication.

Some white supporters had believed that including blacks would seriously weaken the team and turn the Springboks into rugby also-rans.

Kolisi, who last year became the first black Test skipper of the team after 127 years of whites captaining the green and gold, said racial unity sparked success in Yokohama.

"We have so many problems in our country and this team comes from different backgrounds, different races, but we came together with one goal and we wanted to achieve it," he said.

"I really hope we've done that for South Africa. (It) just shows that we can pull together if we want to achieve something."

Kolisi said the Springboks had received countless messages from home as the nation rallied behind his team.

"Since I've been alive, I've never seen South Africa like this," he said.

"Thank you so much. We love you South Africa and we can achieve anything if we work together as one."

However, the selection of six black players in a Springbok World Cup final team has been a long and tortuous journey.

There have been highs like the elevation last year of Kolisi to lead a team that for 90 years chose only whites.

There have also been lows, most recently when star lock Eben Etzebeth was accused of assaulting and racially abusing a homeless black man just before flying to Japan.

Etzebeth, who captained the Springboks two seasons ago after first choice Warren Whiteley was injured, denies the allegations.

Springboks coach Rassie Erasmus is adamant that there are no racists in his charge, telling AFP that "I would not tolerate racism in my squad.

"I can guarantee you that this team is a nice, close-knit one, and there will never be something like that (racism)."

But the coach had to turn firefighter in Japan after celebrations following a mammoth pool win over Italy triggered social media fury.

Six white reserves excluded black starter Makazole Mapimpi from a huddle and the immediate reaction on social media was that the winger had been racially shunned.

In fact, the "bomb squad", as the reserves label themselves, always celebrate separately from the starters.

Mapimpi, the second highest try-scorer at this World Cup with six, backed the reserves on Twitter only to be branded a "sell-out".

Kolisi was also labelled a "sell-out" this year, for suggesting that late former president Nelson Mandela would not have backed Springbok racial quotas.

The 27-year-old, born into poverty in the eastern Cape, does not enjoy being called the first black Test captain of the Springboks.

"That is not a description I find natural," he admitted to AFP before the tournament. "I'm privileged to captain a team that represents all South Africans."

Kolisi was born during the death throes of apartheid in 1991 and three years later multiracial elections ushered long-time political prisoner Mandela to power.

Mandela later played a key role in defusing demands from elements within the ruling African National Congress party that the emblem of a leaping Springbok be ditched.

The political icon reasoned that the Springboks were dear to South African whites and he wanted to foster national unity in the aftermath of the divisive apartheid era.

He arrived at the 1995 World Cup final in Johannesburg wearing a replica of the shirt of skipper Francois Pienaar and a mainly white crowd chanted "Nelson, Nelson, Nelson".

Mandela later presented the trophy to Pienaar after a dramatic triumph over arch-rivals New Zealand, and hopes were high that a new, multi-racial team would be born.

Winger Chester Williams, who died in September of a heart attack, was the lone black in the 1995 team, an unacceptable situation given only 10 percent of the population was white.

But when the Springboks conquered the world again in France 12 years later, there were just two black starters, wingers JP Pietersen and Bryan Habana.

Despite growing government anger at predominantly white teams, a succession of Springbok coaches ignored emerging black stars, until Erasmus assumed control last year.

He offered black players equal opportunities and a record 11 made the trip to Japan with six in the final starting line-up and another on the bench.