Emma Lamb’s maiden international century led England to a dominant five-wicket win over South Africa in the first one-day international at Northampton.
Lamb, in her third ODI, brought up her hundred from just 91 balls as England chased 219 with 17.5 overs to spare.
She added 89 for the third wicket with Nat Sciver, who made 55 from 31 balls.
It was an impressive performance from England throughout, dismissing the tourists for 218 inside 48 overs before never letting their bowlers build any pressure during the chase.
South Africa opener Laura Wolvaardt made 43 before Chloe Tryon smashed an entertaining 88 off 73 balls, including three sixes, and looked as if she would propel her side to a reasonable total.
But her wicket sparked a collapse of five wickets for just 13 runs in the space of 16 balls.
Katherine Brunt took 3-18 in her first international appearance of the summer and Sciver claimed career-best figures of 4-59.
England lead the multi-format series 4-2 after the one-off Test finished in a rain-affected draw.
The second ODI is at Bristol on Friday, starting at 14:00 BST.
Lamb had a difficult start to her ODI career, facing just two balls in her first two matches without scoring a run.
But she showed glimpses of her class and fine form during her knock of 38 in the Test match and grabbed her next chance here with aplomb.
A depleted South African bowling attack without the injured Shabnim Ismail and Dane van Niekerk struggled for consistency and Lamb was able to dominate, knowing she had a below-par total to attack.
Fellow opener Tammy Beaumont was bowled by Marizanne Kapp for one but Sophia Dunkley, promoted to number three, hit back with 22 from 24 balls before she was dismissed lbw by Nadine de Klerk.
Unfortunately for South Africa, the departure of Dunkley only brought in Sciver, who continued her imperious form with a brutal half-century.
After centuries in the World Cup final and the Test match, Sciver took her tally to 372 runs between dismissals before she was eventually caught on the mid-wicket boundary off De Klerk.
Lamb and Sciver scored all around the wicket, playing with expansive freedom to make the chase look remarkably easy.
The Test match between these two sides was England’s first taste of life without Anya Shrubsole and Brunt, the experienced and reliable duo who led the bowling attack for more than a decade.
Shrubsole, 30, retired from all formats of the international game in April while Brunt, 36, stepped away from Test cricket, making this her first international appearance since the World Cup final in March.
England opted not to give ODI debuts to Lauren Bell and Issy Wong after their solid showings in the Test and, with figures of 3-18 from nine overs, Brunt showed why she has plenty more to offer in this format.
Andrie Steyn was first to go, pinned lbw for 14, before Lara Goodall nicked to Heather Knight at slip, with Brunt taking 2-5 in a masterful opening spell.
Brunt then cleaned up Ayabonga Khaka for a duck as South Africa’s batting wilted in the sun.
Sciver started expensively before taking four crucial middle-order wickets, including the key scalps of Tryon and Kapp.
For South Africa, meanwhile, there are real concerns. The bowling attack offered little threat, the batters looked short of confidence other than Tryon and Wolvaardt and Van Niekerk’s inspirational captaincy was missed more than ever.
With two ODIs and three Twenty20s to come, they do not have much time to turn it around.