England made it back-to-back Junior World Championship titles by defeating South Africa 21-20 in Auckland on Friday.
Tries from Nathan Earle and replacement Joel Conlon along with the boot of Billy Burns were enough to see England narrowly home at Eden Park.
Jesse Kriel scored two tries for the Baby Boks who at one stage lead 10-3 before England fought their way into the lead just before half-time.
England were looking to defend their title from 2013 having retained the core of their squad from last year's success in France, but were facing a Baby Boks outfit who had managed to defeat New Zealand twice in their own backyard over the last few weeks.
Even with a misfiring lineout Nick Walshe's team had too much in their arsenal to be denied, defending their title with a strong second half performance.
Maro Itoje, their captain, was outstanding in taking on the physical threat posed by South Africa and leading by example.
HandrÃ¨ Pollard landed the first points of the final after Billy Burns strayed offside, the younger brother of England number ten Freddie responding in turn as a nervy opening quarter ended with the scores tied up at 3-3.
A touch of over exuberance from England deep in their own half left them in trouble. Pollard's chip over the top turned England full-back Aaron Morris inside out as Jesse Kriel capitalised to score the first try.
Defence ruled the roost as both sets of half-backs struggled to maintain any clean possession at the breakdown.
England's lineout persistently let them down in the opening half, Tom Woolstencroft's wayward throwing snuffing out promising field position as the champions looked to battle their way back into the contest. That extra bit of physicality at the breakdown from South Africa was telling.
A penalty from well in his own half from Morris brought England back within four points, the full-back landing a brilliant strike to give his side momentum.
Pollard was lucky not to be sin-binned for a mid-air tackle and England made the Boks pay, working their way upfield through a thundering carry from Nick Tompkins to make the space out wide for Earle to score. It handed England a slender 11-10 lead to take into the interval.
Burns added a second penalty after the break to stretch the lead, Cyle Brink killing the ball as England upped the ante.
Danny Hobbs-Awoyemi's breakdown offence shortly after though handed Pollard the chance to respond, the Bulls number ten cutting the lead back to a single point.
With three points on offer following another breakdown infringement by the Boks, England rejected a kickable penalty and consequently knocked on from their lineout five metres out. On such decisions are finals won or lost.
They were handed a reprieve. Winning another five-metre lineout, England's maul couldn't be stopped as the replacement Joel Conlon scored. Burns' conversion extended England's lead to 21-13.
Burns missed another chance to put more points on the board with a penalty and the Baby Boks duly hit back, Kriel scoring his second try after a breakout down the left from Duhan van der Merwe.
It was always destined to be close. Fired up by the momentum from Kriel's try South Africa continually battered England's defensive line. The assault ended with a drop goal from Pollard which fell wide to the right.
Soaking up the clock with a series of driving mauls, England's pack ground down the remaining seconds to taste glory at this stage once again.
Tries: Earle, Conlon
Pens: Burns 2, Morris
For South Africa:
Tries: J Kriel 2
Cons: Pollard 2
Pens: Pollard 2
England U20: 15 Aaron Morris, 14 Howard Packman, 13 Nick Tompkins, 12 Harry Sloan, 11 Nathan Earle, 10 Billy Burns, 9 Henry Taylor, 8 James Chisolm, 7 Gus Jones, 6 Ross Moriarty, 5 Charlie Ewels, 4 Maro Itoje (c), 3 Paul Hill, 2 Tom Woolstencroft, 1 Danny Hobbs-Awoyemi
Replacements: 16 Jack Walker, 17 Alex Lundberg, 18 Biyi Alo, 19 Hayden Thompson-Stringer, 20 Joel Conlon, 21 Calum Braley, 22 Sam Olver, 23 Henry Purdy
South Africa U20: 15 Warrick Grant, 14 Dan Kriel, 13 Jesse Kriel, 12 Andre Esterhuizen, 11 Sergeal Petersen, 10 Handre Pollard (c), 9 JP Smith, 8 Aidon Davis, 7 Cyle Brink, 6 Jacques Vermeulen, 5 Nico Janse van Rensburg, 4 JD Schickerling, 3 Dayan van der Westhuizen, 2 Corniel Els, 1 Thomas du Toit
Replacements: 16 Joseph Dweba, 17 Pierre Schoeman, 18 Wilco Louw, 19 Victor Sekekete, 20 Jean Luc du Preez, 21 Zee Mkhabela, 22 Jean Luc du Plessis, 23 Duhan van der Merwe
Referee: Ben O'Keeffe (NZ)
Assistant Referees: Matt O'Brien (Aus), Joaquin Montes (Uru)
TMO: Vinny Munro (NZ)