The Proteas were crushed by seven wickets in the third Test against England at the Wanderers on Saturday.
The result means that England now take an unassailable 2-0 lead in the series with only the January 22 Test in Pretoria remaining.
Stuart Broad (6/17) did the damage for the visitors with a spell of bowling that was nothing short of a masterclass, and South Africa were never going to recover from being skittled for 83 in their second innings.
After Kagiso Rabada had taken three wickets in the morning session to finish on a career-best 5/78 and help dismiss England for 323, there was a sense of optimism that South Africa would spend the rest of the day setting the visitors a competitive total.
But Broad had other ideas, and his majestic spell of fast bowling saw the Proteas lose five wickets for just 12 runs as they collapsed.
The Proteas batting had no answer to Broad, and that Rabada top scored with 16 speaks volumes.
England started their second innings needing just 74 runs to win.
They soon found out that batting wasn’t easy – Morne Morkel and Rabada finding the movement that had been such a major factor in Broads’s lethal performance.
But after the England openers had negated the first few overs they looked largely comfortable, and while there was still some playing and missing the Proteas could not manufacture any chances.
With each run the inevitability of the situation grew stronger and while the Wanderers crowd, to their credit, remained hopeful there was never going to be a way back for the Proteas.
With just 10 runs to win England lost Alex Hales (18) when Dean Elgar had him trapped LBW.
Elgar then picked up another when Nick Compton (0) tried to go over the top of the ring only to be caught by Morkel at mid-on.
With just three runs to get and with the floodlights on, Cook then tickled Chris Morris through to Dane Vilas behind the stumps to be dismissed for 43, but even that would have been little consolation for the Proteas.
South Africa have now gone nine Tests without recording a win and are set to lose their No 1 Test ranking at the end of the series.