McCann was stumped on 92 after sharing a 160-run second-wicket partnership with Keshana Fonseka that ensured a powerful response with the bat after Sri Lanka have been all out for 324.
Sri Lanka U19s captain Dinuru Kalupahana had earlier reached his maiden worldwide century with Surrey Academy fast Alex French the decide of the England U19s bowlers with 81 for 4.
The hosts misplaced three late wickets, with captain Hamza Shaikh and Noah Thain rapidly following McCann again to the pavilion, however Fonseka stood agency as they closed on 193 for 4 and with a bit of labor to do with someday remaining.
McCann hit a record-breaking 174, from simply 139 balls, to assist safe victory within the second Youth ODI at Hove final week and once more dominated the vacationers bowling scoring a close to run-a-ball half-century.
England had misplaced Jaydn Denly early, pulling Nathan Caldera straight at Praveen Maneesha, however McCann and Fonseka then took centre stage as they scored at higher than 4 runs an over.
McCann, who signed his first skilled deal at Nottinghamshire final November, appeared set for 3 figures however was undone when a Vihas Thewmika supply stored low as he superior down the wicket.
Shaikh adopted quickly after when he picked out Sheshan Marasinghe off Thewmika earlier than Thain performed again to a Maneesha ball that additionally stored barely low and skidded into his stumps.
Fonseka remained unbeaten on 72, alongside new man and Lancashire team-mate Rocky Flintoff, to go away England U19s 131 runs behind on the shut.
Sri Lanka captain Kalupahana was the star of the primary half of the day to publish his milestone century. The 19-year-old seemed snug within the situations, typified by the stroke that introduced up his century as he eased French backward of level and to the rope.
Kalupahana celebrated the milestone by racing in the direction of his team-mates and leaping into the air.
The skipper had shared a 99-run stand with Diniru Abeywickramasingha, who grew to become the primary of 5 batsmen caught within the ring throughout the day when he mis-timed a drive to Flintoff in entrance of level.
Leicestershire’s Alex Inexperienced then claimed the prize wicket of Kalupahana with the primary ball of his new spell – the second time he has achieved that within the recreation – trapped lbw on the crease.
Thain enticed Thewmika to drive to Flintoff at extensive mid-on after a 45-run eighth-wicket stand with Caldera, who was final man out when he too mis-hit a drive that Shaikh held handy French his fourth wicket.
