After beating Polytechnic 9-7 on day one, they edged out Sheffield Stingrays 11-10. Sunderland recovered from 10-8 down to grab a narrow lead in the third period thanks to goals by Ashley Boardman, Jessica Millar and Samantha Crawford. Eight of the Sheffield goals were scored by Emily Weatherill.
The final period produced four exclusions, three time-outs and a Sunderland missed penalty - but no more goals.
Liverpool Water Beatles, Leeds Hammerheads, English Roses, Birmingham and Southampton progress to Championship 2, with Polytechnic, Sheffield Stingrays and Sunderland left with the option of entering the end-of-season qualification tournament for 2017/18.