Alex Hales struck 99 as England heaped further misery on South Africa with a five-wicket one-day international victory in Port Elizabeth.
Hales struggled for form throughout the preceding Test series, his first, as the tourists ran out winners but the powerful opener has thrived on his return to limited-overs cricket.
Having contributed 57 from 47 deliveries as England racked up 399-9 on their way to winning the opening ODI, Hales was central to a successful pursuit of 263 on Saturday, although he did fall one short of a hundred for the second time in his international career.
On a surface that provided much more encouragement for bowlers than the flat deck used in Bloemfontein on Wednesday, Reece Topley returned ODI-best figures of 4-50 as the Proteas were limited to 262-7 after winning the toss.
AB de Villiers top-scored for South Africa with 73, but the innings lost momentum after his departure to another wonderful catch, this time from Chris Jordan, in the 41st over.
Although England lost Jason Roy (14) early, Hales paced his innings to perfection and put on 97 for the second wicket with Joe Root (38).
There was disappointment for Hales when he was caught down the leg side off Kyle Abbott (3-58) needing a single to reach three figures, but the in-form Jos Buttler (48 not out from 28 balls) duly hurried England to victory in the company of Moeen Ali (21 not out).
South Africa now find themselves 2-0 down in the five-match series, making Tuesday's third ODI at Centurion a must-win fixture.
Home openers Hashim Amla (4) and Quinton de Kock (22) fell cheaply, the latter crucially wasting a review when leg-before to Ben Stokes, but there were solid contributions from the middle order as the Proteas threatened to post an imposing total.
However, Faf du Plessis' innings of 46 ended when he edged Adil Rashid to slip and a stand of 107 between De Villiers and JP Duminy (47) was undermined by both batsmen falling in the space of four deliveries.
De Villiers became Stokes' second victim when Jordan held on to a steepling chance over his shoulder in the deep, before Duminy was left to rue De Kock's rash review as Topley won an lbw verdict despite replays showing the ball was sliding down.
Topley went on to pick up two more wickets as South Africa faltered and England were soon looking good in reply despite Abbott bowling Roy through the gate.
The hard-hitting Hales adopted a measured approach in his decisive 124-ball knock and a late wobble, which saw three wickets fall for 33, was soon forgotten as Buttler took charge - striking three successive sixes off Imran Tahir (0-66) in what proved the penultimate over.