Liverpool eased into a 4-1 lead early on before goals by Vicki Hawkins (2), Ana Nunez-Rueda and Elizabeth Kennedy brought battling Coventry up to 5-5 with 43 seconds remaining of the third period.
That sparked an instant Liverpool response. Within another 20 seconds, Laura Hesketh scored to recapture a 6-5 lead. Further goals were claimed in the final period by Katie Hesketh, Alice Byrne and Grace Rowland before Kennedy netted for Coventry.
Two 16-year-olds - Emmie-Rose Eastwood and Stephanie Whittaker - were both on target four times as Manchester beat Sheffield Sharks 17-9. For Sheffield, the leading scorers were Danielle Elliot (5) and Bernice Cowton (3).