From 10-10 at the end of the third quarter, the Scots looked down and out as three goals from Tom Curwen - who finished the match with six - swept Lancaster into a 13-10 lead.
Fraser Rutherford began the recovery by scoring with just over two minutes remaining. Antonella Padolecchia's sixth goal followed; then Jose Ronaldo struck the equaliser with 30 seconds left on the clock.
Manchester, last year's champions, finally claimed their first victory at the sixth attempt - 15-7 against Bristol Central. Bristol led 3-2 after the first quarter but Manchester coasted through after scoring five goals without reply in the second, including four by Rob Rae.