The hosts posted a staggering 219/1 after being sent in to bat, setting a new Women's T20 World Cup record score and eclipsing the previous mark of 213/5 that England themselves established against Pakistan in 2023.
Sri Lanka, chasing a target never before achieved in the tournament, were dismissed for 132.
The star of the evening was Danni Wyatt-Hodge, who produced a magnificent unbeaten 105 from 62 deliveries. Her innings featured 13 boundaries and a six, making her the first player to reach three figures at this year's tournament. The knock was also the seventh century in Women's T20 World Cup history and only the second by an English player.
It capped a memorable period for Wyatt-Hodge, whose partner Georgie gave birth to their first child on May 20. She reached her hundred with a sweep to the fence and ended the innings by striking the final ball for four as England plundered 26 runs from the last over.
Wyatt-Hodge and Amy Jones laid the foundation with a 135-run opening stand after England raced to 51 without loss in the powerplay.
Jones made 53 from 38 balls despite being dropped on 12 and 48 before falling to Malki Madara, caught by Chamari Athapaththu at mid-off. Captain Nat Sciver-Brunt, recently back from injury, added a rapid 46 from 22 balls.
Sri Lanka's response never gained momentum. Athapaththu departed for four in the fourth over, brilliantly caught behind by Wyatt-Hodge off Charlie Dean. At 39/3 after six overs, the chase was already faltering.
Harshitha Samarawickrama contributed 29, while Nilakshika Silva top-scored with 39. However, left-arm seamer Freya Kemp's superb 4/22, including a spell that briefly put her on a hat-trick, ensured England opened the tournament with a commanding victory.
Niroshan Dickwella is set to return from the wilderness to Sri Lanka's team for the first Test against India, starting in Galle on Saturday, with captain Dhananjaya de Silva backing the wicketkeeper to come good.
Leeds United have completed the signing of goalkeeper James Trafford from Manchester City on a five-year contract in a club-record deal.
India are expected to be without pace spearhead Jasprit Bumrah for their upcoming two-Test series against Sri Lanka after the BCCI medical team advised against rushing his return from a persistent left knee injury.
England defender John Stones has completed his move to Inter Milan after signing a two-year contract with the Serie A champions following the end of his spell at Manchester City.
