Rilee Rossouw smashed his way to a career-best T20 International score as South Africa pushed on from a blistering start to beat England by 58 runs and level their three-match series.
The Somerset top-order batsman posted an unbeaten 96 not out off 55 balls after arriving at 39-1 to steer the tourists to a first innings total of 207-3 at Sophia Gardens in Cardiff.
That proved to be more than enough to see off the hosts, who slumped to a middle-order collapse in response for 149 all out despite a defiant sixth-wicket stand between Jonny Bairstow (30) and Liam Livingstone (18).
The result means the two sides will head to the Rose Bowl in Southampton on Sunday for a winner-takes-all encounter, after the pair were forced to a 1-1 draw in their ODI series by rain at Headingley.
A lively opening stand between skipper-wicketkeeper Quinton de Kock and Reeza Hendricks sparked early fireworks before the former guided Moeen Ali to Jason Roy for 15, paving the way for Rossouw's arrival.
The left-hander, who returned from a six-year T20I exodus at Bristol on Wednesday, managed only four the night before but rolled out a masterfully modulated performance to guide his side through to the interval.
Stands of 73, 31 and 64 with Hendricks (53), Heinrich Klaasen (19) and Tristan Stubbs (15 not out) helped the Proteas to a double-century plus total, with the latter two in particular offering solid supporting performances.
England conjured an element of deja vu in their immediate response, with captain Jos Buttler holing out to Hendricks off the back of a rapid-fire 29 before Dawid Malan (5) and Jason Roy (20) fell to reduce them to 77-3.
The further dismissals of Ali (28) and Sam Curran (2) in quick succession left them at 92-5, staring down the barrel of a hefty defeat, before Bairstow and Livingstone combined for a morale-boosting 36.
But the former's dismissal through a superb catch from Lungi Ngidi off Kagiso Rabada effectively checked any momentum to leave the hosts at 128-6, and the latter's exit less than an over later sparked a tail-end collapse to tee up an intriguing finale this weekend.
Rossouw seizes second chance
Once the hottest prospect in South African cricket the better part of a decade ago, with a first-class top score of 319 posted as a teenager, Rossouw effectively seemed to end his international career in 2017 when he penned a Kolpak contract with Hampshire.
But injury to white-ball skipper Temba Bavuma has offered him an unlikely shot at Proteas redemption, and though his brief four in Wednesday's opening match was more anticlimactic, this proved a masterful display that could well give him a way back into the setup on a regular basis.
Bairstow keeps form afloat as Tests loom
Few players have showcased quite such a rich vein of form of late than Bairstow in Test cricket, and he carried that Midas touch over into the first T20I on Wednesday with a fluidly assured 90 to guide England to victory.
While the hosts fell considerably shorter a day later this time around, Bairstow once again proved their top scorer with a more modest 30, a figure that nevertheless showcases his ability to keep grinding out runs as he prepares to return to the long-form game against the tourists next month.