England's cricketers, it might have been mentioned once or twice in recent times, haven't had a lot of exposure to life out in India. They've seen it all now. And by the end of a delirious night at the Wankhede Stadium, so too had the massed ranks of Mumbaikars in the stands, who clutched the new kids on the block to their hearts.

"England! England!" came the cry - a sentiment that, as an Indian colleague noted, probably hadn't been expressed with such feeling since the days of Queen Victoria. A packed Friday-night crowd, at last fully awake to the global tournament taking place in their midst, gratefully bestowed their largesse on a team who had entertained them with more bountiful exploits than they could ever have hoped to witness.

It was a staggering night of entertainment with more ebb and flow than a time-lapse photograph of Chowpatty Beach. And yet, at the heart of the ceaseless inundating action stood a world-class cricketer whose stillness of thought reduced the commotion all around him to a barely audible mutter.

The closest thing to a false step that Joe Root took throughout a truly great night's work came as he shuffled into the press room, still caked in sweat and adrenaline, and had to reach out for balance as his studs skidded on the concrete floor.

In England's hour of need, and with World T20 elimination looming in the event of a slip off the tightrope, Root's sure-footed guidance resulted in what the man himself later confirmed was his best-ever performance in the shortest form of the game. But it was a tweet from a modern master that really put Root's achievement into the context that it deserved.

Mere seconds after the match, none other than Brian Lara logged on to Twitter to declare: "I'm proud to see a top class TEST BATSMAN ‪@root66 play the most outstansing innings of the ‪#ICCWT20 leading ENG to an impropable win" - the great man's excited rush to share his opinions no doubt contributing to his inventive wordplay.

It's been an unfamiliar direction of travel in recent times - in the earliest years of the T20 revolution, established Test stars such as Jacques Kallis, Sachin Tendulkar and that man Kevin Pietersen made the journey from long-form to short-hand and, on account of their supreme skills, were able to adapt to the new parameters with ease. More recently, however, the reverse has been true, with David Warner being perhaps the best example of an established Twenty20 star taking the step up to Tests and bringing his belligerent strokeplay with him.

But there's nothing remotely belligerent about Root's style of play - his mild manner extends to his flat and unemotional utterances in the media, in which he summed up the thrill of making 83 from 44 balls to secure the second-highest run-chase in T20 International history by saying: "It's just nice to contribute to a game of cricket."

But that is precisely the point of his performances. Root is a man, like Jay Kay from Jamiroquai, who has perfected the art of travelling without moving. He has no need for release shots because he defuses the mounting tension with a constant diet of singles, and he has barely any need for big shots either for precisely the same reason.

The fact that he unfurled four sixes today was a tribute to the task he had been set - he had never hit more than two in any of his previous 13 T20I innings. However, his technique was more than equal to the task, never more stunningly than when he turned his stance inside-out to flick Chris Morris over the rope at third man. As it happens, Root once tried, and failed, to pull off that shot in an Ashes Test at Lord's. But the big-game practice clearly paid off. Today he nailed it when it truly mattered.

Such cherries, however, were nothing compared to the perfection of Root's icing. Of the 44 deliveries that he received today, he failed to score from precisely three: a third-ball bouncer from Kagiso Rabada that he vehemently argued was a wide, as well as a penultimate-ball yorker followed by a full toss that had him caught on the midwicket boundary from the same bowler, by which stage his efforts had already whittled the requirement down to 11 off 10 balls.

Urgency didn't come into the equation, but then it never does. He plays this trick all the time in Test cricket - in January, for instance, he set up England's series-sealing win with a sensational century at Johannesburg, a proper gritting of the teeth in high-kicking Highveld conditions. Despite coming to the crease at 22 for 2 in the 11th over and being hounded by Hardus Viljoen and Morne Morkel from the outset, he still breezed his way to 110 from 139 balls all told. That's roughly the same strike-rate, 79.13, that Eoin Morgan and Moeen Ali finished with today, 80.00, in the World T20's greatest run-chase.

"The best thing about today, really, was it wasn't a complete performance," Root added. "We didn't play at our absolute best and we can still chase down a score like that. That will give everyone in the squad massive confidence."

What gumption, though, from the England team as a whole - a side still learning on the hoof, but who managed to take a whupping from Chris Gayle on Wednesday and somehow distill the lessons of that innings in the space of 48 hours.

"I think more than anything, his innings showed us that anything is possible in these conditions on a wicket like that," said Root. "Knowing that you have so much strength in your batting behind you, it gives you licence to be a bit more experimental and a bit more risky."

No one took that licence more literally than the unsung hero of England's innings, Jason Roy. On Thursday morning, Jos Buttler had been asked what England could have done better with the bat in their defeat against West Indies. His response had been a gentle but telling nudge in the ribs for both Roy and Alex Hales, whose solid start to England's campaign had fallen well short of being spectacular.

His words, though softly spoken, must have stung like a cattle prod. In a contest that hinged ultimately on the "execution of skills", Roy court-martialled South Africa's new-ball bowlers for desertion and dispatched them by firing squad. His chanceless, sumptuous 43 from 16 balls included five fours and two sixes in the space of his first eight balls, as Kyle Abbott and Dale Steyn were given the hiding of their lives.

"Without that start, it would have been very difficult," said Root. "The guys up front were fantastic, they got us ahead of the game straightaway and gave us a bit of breathing space in the middle overs if things didn't exactly go to plan."

"The best thing about today, really, was it wasn't a complete performance," he added. "We didn't play at our absolute best and we can still chase down a score like that. That will give everyone in the squad massive confidence."

It was telling, too, from the manner in which England shuffled their batting, with Stokes thrust up to No. 3 to continue the spanking while the more staid pairing of Root and Morgan hung back ready to restore calm in the middle overs, that England were happy to gulp in deep breaths of air and let the chase settle at crucial moments.

"When you get off to a good start, you can just go and play and back your natural instinct," said Root. "If previously the bowlers have gone at 20 an over, they are under pressure and have to drag it back, so that means we could build partnerships. When you've got guys at the other end like Jos, and Morgs, who've done special things in the short format of the game, and they are talking you through it and keeping you calm, it helps to take the pressure off."

No passage of play was more crucial than England's negotiation of Imran Tahir, the one man who might have derailed the chase had he been allowed to mix it with a rash of swishing blades. He did eventually claim one scalp, that of Buttler, stumped down the leg side, but by that stage he only had two deliveries left of his allocation and his threat had largely passed.

England's own spinners, by contrast, reeled South Africa with three important strikes after their helter-skelter start - with Adil Rashid's outfoxing of the hyper-aggressive AB de Villiers a pivotal moment of the match. It felt like a pyrrhic victory at the time - Rashid's over still disappeared for two sixes and 14 runs, but de Villiers' departure sucked the wind out of the stadium, and Faf du Plessis in particular proved to be out of puff.

"They've been crucial for our success for a number of months now," said Root of England's spinners, Rashid and Moeen. "They are developing all the time and gaining experience."

Moeen's final contribution, of course, was to strike the winning runs, a feat that he achieved in spite of the mounting tension of the final over. Root by this stage had departed, but not before a long chat of encouragement to his partner.

"I just said stay calm, you've got more time than you think in this format of the game," Root said. "The bowler's under more pressure than you are, so stay nice and relaxed. Thankfully he managed to get us across the line."

When asked how England build from this moment, Root responded with his deadest bat of the night. "Take it game by game," he said. "I know it's a boring response, but all we can do now is keep momentum, because one bad result from now on and we could be out of the tournament."

It was the sort of rational calculation he had been applying all evening long.

Andrew Miller is UK editor of ESPNcricinfo. He tweets @miller_cricket