"Cricket's coming home," they sang as the players left the field. And while such celebration was no doubt premature, the enthusiasm was understandable.
For this was a deeply impressive start from England. This South Africa team is dangerous - they are No. 3 in the world rankings, after all - and winning the toss in these conditions was a significant advantage. Victory may well settle some nerves in their dressing room.
But perhaps as important as the win was the manner in which it was achieved. We have known for some time that, on good batting tracks, England's batsmen could dominate. We knew they had a Plan A. And we have known for some time that Ben Stokes was a cricketer of supreme natural talent who could, on his day, win games with bat, ball and in the field. The catch he took here - described by Faf du Plessis as "as good as it gets" and Eoin Morgan as "unbelievable" - was a reminder of that.
But questions remained about how England could adapt on surfaces requiring more subtlety. Surfaces where bowlers could gain purchase with cutters or spin and where 280 might be considered par. Surfaces where they required a Plan B. The last ODI they played against South Africa in this country saw England subside to 20 for 6 in bowler-friendly conditions. You don't win many games from that position.
And perhaps a few questions remained about Stokes' form. His naturally aggressive game isn't ideally suited to such circumstances and he hasn't been quite the same irrepressible figure since he returned to the side in February 2018. He endured, by his standards, a modest IPL season - he averaged 20.50 with the bat and failed to make a 50 - too.
So for Stokes to oversee an England effort when Plan B was applied so effectively was all the more pleasing from an England perspective. There was a moment, after the drinks break that was taken when England had faced 34 overs, when it seemed Stokes had the license to unleash his full aggression. Four of his next nine deliveries were hit to the boundary and it seemed the foot would be kept on the accelerator.
But then Morgan fell. And with Jos Buttler and Moeen Ali following not long afterwards, Stokes reasoned that his role was to ensure England adopted Plan B. So instead of looking for boundaries - he hit only one more in the next 11 overs - he instead concentrated on placing the ball into gaps, running hard and saving something for a burst in the final three or four overs. It was a calm, mature performance from a man - and a team - more characterised for their aggression and passion.
"The pitch was slow," Morgan said. "It never allowed you to get away and strike the ball like we would do for Plan A.
"But one of the areas of our game that has improved last two years is the way we've assessed conditions and played more smart cricket. We build partnerships and put a total on the board we believe is enough. At the halfway stage we didn't believe that we had enough but we believe we had around par."
That is significant progress. A couple of years ago, in their desire to reach 350, England may well have struggled to make 250. Here, on a surface where Moeen reckoned 270-290 was par, England still managed to surpass 300 (the 39th time they have done so since the 2015 tournament; they had managed it just 34 times in total in the 40-plus years they had been playing in this format previously) with Stokes registering his highest score in any format of international cricket since August 2017.
To add a wonder catch and two wickets to the performance underlined his immense value to the side. He later described it as "a perfect day."
"The best thing about being an all-rounder is being able to influence the game for the whole 100 overs," he said. "It's always nice when you can contribute to the team winning.
"But the most pleasing thing is we have got the first game out of the way. There were a few nerves knocking about - there definitely were for me; I have not felt like that in a long time - so it's great to walk away with a win."
Morgan said: "He's at the top of his game. When he plays like that is extremely entertaining. It's great for the game. His all-round game was on and that's great for us at the start of the tournament."
Moeen agreed with Stokes' assessment of the team's mindset: "Everyone was nervous. Losing the toss, starting at 10.30am and being both the home and No. 1 ranked side, it felt like the pressure was on. We adapted really well. That's a great win that really settles the nerves."
This was not a one-man performance, by any means. Three other men scored half-centuries, while Jofra Archer's new-ball burst made vital inroads into the South African batting.
"No-one wants to face him," Moeen said afterwards. "He's the fastest bowler I've ever faced. He unsettles people."
England's fielding was also rated by Stokes as their "best for a couple of years," while all the bowlers could feel satisfied with their day's work.
But Stokes is a talismanic player for England. If he is edging back towards his best - and, bearing in mind he made a match-winning 71 against Pakistan two ODIs ago, all the evidence suggests he is - England have an all-rounder that can shape games in every discipline and who gives them enviable depth with bat and ball.
By the end of this game, his smile was as broad as at any time in many, many months. It all bodes well for England.