Mendota and L-P will meet for the Rock Falls 3A regional championship on Friday.
The Trojans knocked off the host Rockets 70-57 in Wednesday's first sectional semifinal.
L-P ousted rival Ottawa in a big way 73-49 in the nightcap.
Friday's title tilt will start at 7:30 p.m.
Byron 2A Sectional: Winnebago downed Aurora Christian 69-51 while Sterling Newman surprised Seneca 45-27 in sectional semifinal play Wednesday.
Granville 1A Sectional: No. 1 ranked Mason City Illini Central dispatched Decatur Christian 71-62 in Wednesday's sectional semifinal contest at Putnam County High School.
IC (24-7) awaits Thursday's winner between the host Panthers and Colfax Ridgevew.
Newark beat Chicago Hope Academy 61-51 at the Mooseheart 1A Sectional.