Kaitlyn Wenz scored eight of her game-high 22 points in the fourth quarter as the Bulldogs held off the host Cougars.
Katie Rathgeber added 19 points and hit two key free throws in the final minute to keep Seton at bay. Stevenson (11-4, 4-1) trailed midway through the third quarter, but outscored Seton 20-15 in the fourth.
Wenz also had 12 rebounds and five steals. Rathgeber added six rebounds and three steals.
Jasmine Morgan had 17 points and 10 rebounds to lead Seton (6-9, 1-4).
STEVENSON 64, SETON CATHOLIC 60
STEVENSON — Jaida Emerson 8, Cassie MacNab 6, Katie Rathgeber 19, Jazmine Morat 3, Ashley Brannan 6, Alisyn Backlund 0, Kaitlyn Wenz 22, Sara Campbell 0. Totals 24 (1) 15-38 00.
SETON CATHOLIC — Haley Vick, Michaela Ephraim 4, Emma Watkins 14, Katie Willis 6, Jasmine Morgan 17, Madi Manary 0, Claire Kirn, Jerrica Pachl 4, Aislynn Hogan, Maddie Willis 13, Cailean McGovern 2, Abigail Wall 0, Katherine Zdunich 0. Totals 23 (3) 11-19 00.