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.
Shemaine Campbelle blasted 90 not out to carry the West Indies Women over the line against T20 World Cup holders New Zealand Women in Southampton on Saturday night.
South Africa's Women's T20 World Cup campaign began with a disappointing 65-run defeat to Australia as a record chase proved beyond them.
Jarell Quansah has attributed his place in England's 26-man World Cup squad to the difficult decision to part ways with Liverpool to join Bayer 04 Leverkusen last year.
England continued their preparations for the 2026 FIFA World Cup with an impressive 3-0 victory over Costa Rica in Orlando, as Anthony Gordon delivered a standout performance in their final official warm-up match before the tournament.
