England bowled South Africa out for 274 runs on Monday to win the fourth Test in Johannesburg by 191 runs and ensure an emphatic 3-1 series victory.
Mark Wood took four wickets as the home team crumbled in the evening session after threatening to offer stoic resistance earlier in the day.
England completed the task with a day to spare with South Africa falling well short of their 466 run target in what would have been the highest fourth innings Test chase.
The success is a massive boost for a young English team who overcame illness, injuries and an opening Test defeat by winning the series and calming questions over Joe Root's captaincy.
For South Africa, it marked a 108-year low as they lost for the eighth time in their last nine Tests for their worst run since 10 defeats in 11 tests between 1910 and 1912.
Wood took 4-54 and Stuart Broad and Ben Stokes added two more for England as they took the last six South African wickets for 39 runs.
The home team were facing a near impossible target of 466 and provided some resistance but lost wickets at crucial intervals.
Rassie van der Dussen scored 98 before being tricked into offering an easy catch, just five balls after captain Faf du Plessis had been bowled for 35.
Their 92-run partnership for the third wicket kept alive unlikely home hopes after South Africa were 90-2 at lunch.
Quinton de Kock hit another swashbuckling knock, but by the time he fell for 39 runs with eight wickets down the contest was already over.
South Africa's batsmen ended any pretence at trying to bat out the game after going to tea at 180-4.
Van der Dussen, who lasted seven balls and did not score in the first innings, was given out leg before wicket to Chris Woakes with just the third ball he faced on Monday.
The South African almost ran out of time as he dithered over whether to review, but then won a reprieve as the ball was shown to be missing the wickets, and the umpire’s decision was overturned.
Van der Dussen, promoted up the order, had been the subject of criticism after the third Test in Port Elizabeth for his timid approach to England's spinners but when part-timers Joe Root and Joe Denly came onto bowl he hit them to all corners.
He hit 15 fours and two sixes in a boundary-filled innings and will be livid with the way he went out, essentially ending hopes of fairytale for both himself and his team.
Temba Bavuma and De Kock peppered the boundaries immediately after tea but the writing was on the wall.
Broad returned to the attack and struck twice in his first two overs, Bavuma arching his back dramatically as he gloved behind and Dwaine Pretorius top-edging to fine-leg.
Vernon Philander came out to bat with a torn hamstring but his final act before retirement was a short one, strangled down leg by Wood.
Beuran Hendricks was run out and the series was settled in England's favour when Buttler and Wood combined for Anrich Nortje's wicket.
