The No. 5 seeded Dade County girls got 13 points from Tori Gass in a 30-23 upset of No. 4 Trion.
Jaden Morrison had eight points for the Lady Bulldogs.
In boys' action, the No. 5 Rossville Bulldogs overcame a 20-8 halftime deficit to beat No. 4 LaFayette, 46-39.
Grayson Moore had 17 points and Codarius Word added 15 in the come-from-behind victory.
T.J. Hawkins paced the Ramblers with 19 points in defeat while Kadarrin Ramsey finished with eight.
The semifinals are set for today, starting at 4:30 p.m. with the No. 1 seeded Lakeview girls taking on No. 5 Dade County. The second girls' semifinal will tip off at 7 p.m. as No. 2 Gordon Lee faces off with No. 6 Ringgold.
The other two semifinals will include the No. 1 Gordon Lee boys squaring off with No. 5 Rossville at 5:45 p.m. and No. 2 Heritage battling No. 6 Lakeview in the nightcap at 8:15.
The girls' championship game gets going at 12 p.m. on Saturday with the boys' game to follow at 2.