Regina Dominican 63, North Chicago 56: At Vernon Hills, senior guard Erin Gavin scored a game-high 20 points to lead the No. 3 seed to victory.
Gavin scored 8 points in the fourth quarter, after the Panthers led just 47-41 after three. Gavin also had 3 steals in the game.
"It's just pure effort with her," Regina coach Kerry Durham said. "She brings such energy to this team, especially defensively. She causes a lot of problems for the other team."
Regina (22-8), which won only 6 games last season in Durham's first year, will play top-seeded Vernon Hills (28-2) in Thursday's 7:30 p.m. regional final. Maggie Palmer (15 points) and Caroline Adamczyk (12) also scored in double figures for the Panthers.
North Chicago (13-15) received 16 points and 6 rebounds from 6-foot freshman Tineesha Coleman. Dara Tanner added 14 points for the 10th-seeded Warhawks, and Natajjae Franklin had 9. North Chicago also got 8 rebounds apiece from Justice Moore and Lyric Pearson.