Both Ireland and France had submitted bids to stage the 10th edition of the tournament but, following an assessment of the three bids, only a surprise turnaround from the World Rugby Council would appear to stop the global showpiece heading to South Africa for the second time.
"This is the first Rugby World Cup host selection to take place following a complete redesign of the bidding process to promote greater transparency and maximize World Rugby's hosting objectives," World Rugby and Rugby World Cup Limited Chairman Bill Beaumont said in a statement.
"The comprehensive and independently scrutinized evaluation reaffirmed that we have three exceptional bids.
"But it also identified South Africa as a clear leader based on performance against the key criteria, which is supported by the Board in the recommendation."
South Africa, which also hosted the 1995 Rugby World Cup, promised a "triple win tournament" that would deliver "record receipts," a "bucket-list destination" and "the most athlete-centric event in the tournament's history."
The nation boasts a rich rugby heritage, having twice won the most prestigious prize on offer in the game, and much of the necessary infrastructure is already in place following the 2010 FIFA World Cup -- the first time fooball's biggest tournament had been staged on the continent.
"This nomination is reward for an outstanding bid in which no detail was too small to be addressed or any question not comprehensively answered," said South Africa Rugby chief executive Jurie Roux.
"We are 100% confident that the commitments we made in our document will be delivered. We will make all of world rugby proud of South Africa 2023."
Ireland, previously the bookmakers' favorite to secure the tournament, was let down in the "venues and host cities" criteria. It ranked third with 72.25%, while France was second with 75.88% and South Africa rated highest with 78.97%.
But Irish bid committee chairman Dick Spring insists they're not giving up yet.
"While it is disappointing not to have received the initial recommendation there is nothing in the report which is insurmountable and this is certainly not the end of the road," said Spring.
"We absolutely believe Ireland can secure the tournament for 2023."
The 2023 World Cup coincides with the 200th anniversary of the birth of the game.
Despite the nation's readmission in 1992 to international rugby, after years of apartheid-enforced sporting isolation, South Africa used home advantage so well that the debutants reached the World Cup final in 1995.
The sporting, political and human drama was told in John Carlin's book "Nelson Mandela and the Game That Made a Nation" and was made into the movie "Invictus," with Morgan Freeman playing Mandela.
Carlin tells the story of the moment on the day of the final when white South Africans took a man they once considered a terrorist into their hearts.
"The day's crowning moment came before the game had even begun, when Mandela went out onto the field, before a crowd of 65,000 that was 95% white, wearing the green Springbok jersey, the old symbol of oppression, beloved of his apartheid jailers," he wrote.
"There was a moment of jaw-dropping disbelief, a sharp collective intake of breath, and suddenly the crowd broke into a chant, which grew steadily louder, of 'Nelson! Nelson! Nelson!'"
Two hours later, the day's images adopted iconic status as the "Rainbow Nation" beat New Zealand to win the tournament, precipitating widespread celebrations, increased harmony and a mixture of both pride and hope to a South Africa in desperate need of reconciliation.
The photo of team captain Francois Pienaar receiving the trophy from Mandela, who was wearing the No. 6 jersey associated with the Springboks' Afrikaner skipper, now takes a place of pride at the Apartheid Museum in Johannesburg.
The World Rugby Council will make its final decision regarding the 2023 tournament on 15 November 2017.
Japan is the 2019 World Cup host.