England chased down South Africa's 262-7 with ease to win the second one-day international by five wickets on Saturday and take a formidable 2-0 lead in the five-match series.
Opener Alex Hales set up England's chase with his 99, and Jos Buttler sent England racing to 263-5 with nearly four overs to spare with his 48 not out from 28 balls, which included three sweetly-struck sixes.
England needs to win just one of the three remaining one-dayers for a series win to follow up its 2-1 victory in the tests.
South Africa's total was competitive on a slow pitch at St. George's Park that could be difficult to bat on at times. But England adjusted to the conditions easily and cruised home with another strong batting display after racking up 399-9 to win the first game.
left-arm seamer Reece Topley earlier took a career-best 4-50 for England to curtail South Africa, while Ben Stokes chipped in with 2-54.
Hales only just missed out on a second one-day international century when he went for a pull shot to a short leg-side delivery and gloved it behind to wicketkeeper Quinton de Kock. Joe Root was again solid for his 38 and Buttler, who scored a riveting century in the first ODI, got the job done in double-quick time as he and Moeen Ali (21 not out from 15 balls) put on 61 in just 30 balls.
Ali sealed victory with successive fours off Morne Morkel after Buttler had clattered three sixes in a row off legspinner Imran Tahir the over before.
Topley was pivotal in slowing South Africa's batsmen after the Proteas were set for a late surge and a good total when on 205-3 in the 41st over.
South Africa captain AB de Villiers fell for 73 to Stokes and JP Duminy for 47 to Topley three balls later.
Brief Scores:
South Africa: 262/7 (AB de Villiers 73; Topley 4/50) lost to England: 263/5 (Hales 99, Buttler 48; Abbott 3/58) by 5 wickets.