In pursuit of a massive 235 for victory, South Africa made a tottering start and only a breakout knock from Tristan Stubbs on debut, with 72 from 28 deliveries, kept the game alive as a contest until the penultimate over
Bristol: England 234-6, South Africa 193-8 - England won by 41 runs
Jonny Bairstow and Moeen Ali gave England the perfect launchpad as the home side won the first of their three T20 internationals against South Africa at a canter.
Bairstow continued his excellent summer with his best score in T20Is - 90 from 53 balls - while Moeen made England's fastest fifty in the format, from just 16 deliveries, as England posted an intimidating target, in the face of which the Proteas wilted.
In the chase, South Africa made a tottering start and only a breakout knock from Tristan Stubbs on debut, with 72 from 28 deliveries, kept the game alive as a contest until the penultimate over.
Bristol's small dimensions allowed for both sides to free their arms and hit happily through the line of the ball - 29 sixes were struck over the course of the 40 overs, more than in any previous T20 in this country.
England take the 1-0 series lead to Cardiff on Thursday, where the straight boundaries are perhaps even smaller. Those fans with tickets can expect a similar outcome.
Jos Buttler flew out of the traps, looking to take maximum advantage of the modest confines of the County Ground, but his flashbang knock was ended at 22 - and after a pair of sixes - when David Miller took a tumbling catch at long-off.
Moeen Ali made a 16-ball fifty for England [Getty Images]
Jason Roy was less explosive and departed in the powerplay trying to find a release shot - caught at point by Heinrich Klaasen off a leading edge after he was outfoxed by Lungi Ngidi's slower ball - before Dawid Malan and Bairstow sought to inject impetus into the innings.
Malan was particularly classy in his contribution, clipping one glorious six over midwicket and another regal strike over extra cover in his 43 from 23 deliveries, before he edged Andile Phehlukwayo behind to Quinton de Kock.
Bairstow, though, went on. The Yorkshireman reached his half-century in 36 balls, picking on Tabraiz Shamsi whenever the leg-spinner threw down a short ball - which, unhappily for the South Africans, was much more regularly that would have been desired.
Bairstow was dropped on 58 by Rilee Rossouw, running in from deep midwicket, the delivery after he had clattered Stubbs down the ground for six, as England looked to ramp up the pressure on the Proteas' attack at the death.
Stubbs, called into the attack after South Africa's frontline bowlers had struggled to contain England, went for 20 in his solitary over - including a back-foot no ball, before Bairstow picked off Phehulkwayo for back-to-back sixes at the start of the 17th over, the second of which disappeared into the nearby houses.
South Africa's bad case of dropsy continued when Reeza Hendricks spilled a simple chance at long-on off Phehlukwayo, and England did not so much rub salt into the wound as pour in an ocean as the over went for 33, with Moeen striking three sixes from the last three balls. Never before had an England side managed as many runs in a single over, in any format of the game.
Bairstow was dropped for a fourth time in the 18th over, bowled by Ngidi, as Klaasen was unable to hold on a deep backward square leg, and South Africa's outfielding skills deserted them.
Moeen - who is known to like scoring quickly in Bristol - raced to his half-century with a gentle, lofted six over midwicket off Ngidi, but nicked the same bowler through to de Kock on 52. Liam Livingstone quickly followed, in the same fashion for 5, and Bairstow eventually departed after holing out to Rossouw off Ngidi for 90.
Tristan Stubbs hit 72 from 28 balls for South Africa [Getty Images]
South Africa did not get the start to the chase they wanted, with de Kock leathering a back-foot drive at Malan in a packed cover region off Reece Topley, while in the same over Richard Gleeson took an excellent running catch at third man to dismiss Rossouw.
Hendricks provided the resistance for the visitors, taking on the English seamers through both legside and off - while enjoying a little luck, particularly against the express pace of Gleeson. Quickly, though, it became obvious that the scale of the chase was beyond Hendricks and his teammates.
Klaasen popped Adil Rashid to Chris Jordan in the deep for 20, Hendricks went for 56 - thrashing a towering catch to Sam Curran at deep midwicket off Moeen, and by the end of the 11th over the required rate was already topping 16.
Stubbs, who warmed up for this tour by playing for the unofficial Mumbai Indian second-string on their trip to the UK, did his utmost to keep his country in the game with a series of emphatic blows off both seam and spin, but the youngster needed support. He did not get it from his captain, Miller, who sliced to long-off off Rashid, where Jordan took a tumbling catch. Miller's contribution had been 8 from 12 balls.
That did not deter the 21-year-old, who continued to treat the England bowlers with disdain. Gleeson was hit, baseball-style, down the ground for six. Curran was picked up over square leg when he missed his yorker length. Rashid over-pitched and was swiped over extra cover. No wonder Mumbai rate this kid so highly.
For a brief moment, it seemed conceiveable that Stubbs could take South Africa come, but Jordan's miserly 18th over - which went for just three singles - scrubbed any such dreams.
Instead, the tourists were left needing 51 from 12 balls. And in pursuing that, Stubbs picked out Roy at long-off.
Gleeson backed up the wicket of stubbs by bowling Kagiso Rabada, before removing Phehlukwayo with a slower full toss which was clipped tamely to Rashid at square leg to leave the Lancashire seamer with figures of 3 for 51.