Thornton and Raymond Terrace play off for the Hunter Valley Cup T20 crown at Lorn Park from 2pm.
Runners-up in 2017, Thornton beat Northern Suburbs at Robins Oval after restricting them to 120.
Thornton were always ahead of the run chase and captain Jake Moore hit the winning runs to finish on 41.
Raymond Terrace, who were beaten finalists in 2016, kept A-grade team Port Stephens to 124 and quickly got the score card above the required six-runs an over.
They will be looking for quick revenge against Thornton, who ended their unbeaten start to the regular first grade season with a five-wicket win on Saturday.