Eoin Morgan's 10th one-day hundred for England proved decisive as the hosts downed South Africa by an emphatic 72-run margin in the Royal London Series opener at Headingley.
Morgan's 107 was a real captain's contribution, paced intelligently over 93 balls and punctuated with five muscular sixes and seven fours.
The Dubliner had spoken excitedly about welcoming Ben Stokes and Jos Buttler back from the Indian Premier League and into the middle order.
However, Morgan left their contributions in the shade as he steered the Champions Trophy favourites to 339 for six and past the format's No.1 side.
He said: "It was a pretty good day at the office. You can't be sure what's a good score on here.
"I have felt good for a while. I didn't play as much in the IPL as I would have liked but I got a few runs in the Ireland game and to continue that is a good feeling."
Asked how happy he is that he picked Moeen Ali, Morgan said: "You know what, if we didn't get many runs or wickets I probably would have still picked him. I think he's a fantastic player!"
Moeen also shone with 77 not out as 102 runs in the last 10 overs took England to their highest home total against the Proteas. Moeen, surplus to requirements in the recent Ireland series, also took two wickets, but it was another IPL returnee, Chris Woakes, who finished things off to post four for 38.
South Africa were briefly in the hunt when Hashim Amla (73) and Faf du Plessis (67) combined but fell well short and were dismissed for 267 with five overs remaining.
The tourists won the toss and, after a minute's silence dedicated to victims of the Manchester terror attack, had a compliant Jason Roy caught behind early.
The partisan Yorkshire crowd were hardly dismayed by Joe Root's early arrival, but he was the junior partner in a 98-run partnership with Alex Hales, who peppered the boundary en route to 61 before wafting at Andile Phehlukwayo's first ball.
Root was positioned to anchor the innings but, by the time he flapped Phehlukwayo's bouncer to mid-wicket, his 37-run contribution had become pedestrian.
Neither of their returning danger men made much of an impression, Stokes (25) drilling Kagiso Rabada down David Miller's throat and Buttler (seven) flicking Chris Morris obligingly to short fine-leg.
But it was a different matter when Morgan went after Phehlukwayo, off whom he struck 42 of his runs and four of his sixes.
Spinners Imran Tahir and JP Duminy had been a good bulwark but, after 46 balls without a boundary off their bowling, Morgan opened the floodgates with three in the space of six deliveries.
The loss of Stokes and Buttler threatened to hobble England, but Morgan and Moeen shared a heady stand of 117.
Morgan reached his ton with a maximum, hoisting Rabada behind square.
And though he fell soon after, feeding Morris to cover, Moeen was on hand to keep the accelerator floored.
He flogged Tahir for three sixes in the 45th over and ended the innings in similar fashion with another.
The Proteas did briefly threaten with Amla and Du Plessis, but ultimately fell well short.