The reigning world champions were thrashed 40-7 by the All Blacks last weekend, having been humbled 39-20 by the Wallabies seven days earlier, with national and international media highly critical of de Villiers' decision to select a second-string XV on both occasions.
But de Villers, who took over from Jake White shortly after South Africa's second global triumph in 2007, insists the Boks remain on track to win a third World title.
"I am 90 per cent sure that we can bring back the honours of the World Cup," de Villiers told the Beeld newspaper after being called before the South African parliament's portfolio committee on sport and recreation.
"Next year people will forget two losses but for four years people will remember who the champion of the world is."
But while de Villiers is adamant that the Boks' World Cup defence remains on track, he dos admit that improvements will be need to be made prior to their opening Pool C clash with Wales on September 11.
De Villiers has highlighted his side's finishing abilities and their conservative approach, even admitting that the strength in depth within the squad isn't as strong as he would like.
"We need a killer instinct," added De Villiers.
"At the moment we lack the ability to land a knock-out blow when our opponents are against the ropes.
"There is an extreme fear of hazardous rugby and the standard of certain players is also a concern."
South Africa's disappointing results against their southern hemisphere rivals were hardly surprising given that they toured Australasia without 21 front-line players.
Star names such as Bryan Habana, Fourie du Preez, Victor Matfield, Bakkies Botha and Juan Smith were all left at home to recover from injuries, although critics suggested their absence was nothing more than a deliberate ploy to rest players ahead of the World Cup.
De Villiers has again defended his stance, however, insisting once more that he had no choice but to leave so many of his key men behind.
"I could not go against the guy [medical doctor], whom I pay a lot of money for his opinion, and say I don't need your opinion.
"In a normal year we would risk five or six of those injured players in the Tri-Nations, but this is not a normal year."