The South Africans had tackled themselves to a standstill last week against Wales on the way to 17-16 win and assistant coach Gary Gold had said he did not want to endure a similar performance against Fiji.
On Saturday they took heed of Gold's advice to dominate the breakdown and provided scrumhalf Fourie du Preez superb quality ball to free his hard running backline and seize their scoring opportunities when they arose.
Flyhalf Morne Steyn scored 21 points through a try, five conversions and two penalties as the Springboks grabbed a bonus point and went top of the "Pool of Death" that also includes Wales, Samoa and Namibia.
After flyhalf Steyn surprisingly missed an early penalty attempt, inside centre Frans Steyn opened the scoring with a mammoth penalty from eight metres inside his own half.
Fiji inside centre Seremaia Bai equalised 10 minutes later after the Springboks were caught offside at the ruck following a sustained period of attack.
The South Africans, however, turned the momentum of the match with an eight-minute period when they dominated the breakdown, recycled the ball quickly and scored 15 points with two tries to loosehead prop Gurthro Steenkamp and centre Jaque Fourie.
Morne Steyn converted Steenkamp's try and added a penalty as the Springboks went out to a comfortable 18-3 lead, which Steyn extended to a 21-3 advantage on the stroke of halftime.
Fiji again tried to play an up-tempo style in the second half but once Frans Steyn gathered a chip kick from openside flanker Heinrich Brussow to score in the corner nine minutes into the second half, the game effectively ended as a contest.
Morne Steyn scored his fifth international try when he finished off another clinical attack inside the Fijian 22-metres area, while replacement prop Tendai Mtawarira scored his first test try, and man of the match Danie Rossouw crossed for a well-deserved late try.
Fijian winger Naipolioni Nalaga had two tries ruled out, the first for a forward pass and the second when he dropped the ball while diving over the line.