Overton built a 27-17 lead in the first half before opening up a 44-29 advantage early in the fourth quarter en route to claiming the 12-point win.
Although Marshall County committed only 13 turnovers, the Tigerettes were unable to find the range against the Lady Bobcats 2-3 zone and shot just 26 percent (17-of-66) from the field, which included a 3-of-20 effort from three-point range.
MCHS did hold a slight 18-17 edge on the offensive boards, but Overton outrebounded Marshall County 39-35 overall.
Aided by a 5-of-7 shooting performance in the fourth quarter, the Lady Bobcats shot 40 percent (23-of-58) from the floor despite making only 1-of-9 attempts from beyond the arc.
Forward Tresti Patton paced Overton with 16 points and 10 rebounds, while Torry Patton notched 12 points and 17 rebounds. Jay Bond also added nine points and LaShae Brown chipped in seven points. Meme Graham, Cachey Grahm and Avei Logoleo rounded out the scoring for the Lady Bobcats with five, four, and two points respectively.
The Tigerettes inched out to a 10-8 lead late in the first quarter thanks to four points from Lyttle and baskets from Morris, Hargrove, and Reed, before Overton rattled off six straight points to pull ahead 14-10 early in the second period.
Marshall County trimmed the deficit to 17-14 midway through the second quarter on a Morris layup and a jumper by Hargrove, but the Lady Bobcats responded with a 10-1 spurt to forge a 27-15 advantage with :26 left in the half.
After Moyers hit a jumper as time expired in the first half to make it 27-17 at the break, the Tigerettes outscored Overton 12-9 through the first 5:50 of the third period with the help of two Moyers treys and four points from Hargrove to narrow the gap to 36-29.
The Lady Bobcats, though, kept MCHS at arm's length by tallying eight consecutive points to push their lead to 44-29 with 5:45 left in the fourth quarter.
Marshall County put together a 12-6 run behind four points from Hopkins and a Moyers three to narrow the gap to 50-41 with 1:25 remaining, but Overton scored the next five points to open up a 55-41 advantage before taking home the 55-43 victory.