The Griffins (19-13) came out swinging early after the break and ran their lead to 32-20, prompting a timeout from McDonald. From that point on, the Falcons shifted into another gear.
Fairmont committed just four turnovers and shot a scorching 58.3 percent after halftime, while holding Seton Hill to 37 percent.
"At times we didn't have the ability to score or get stops," Seton Hill coach Ferne Labati said. "We kind of broke down.
"It happened to us the last game, the last time we played them at the very beginning. When it happens at the beginning, and we were down 12 at the half at Seton Hill, we were able to regroup and recover. When they made their run and pulled timeouts, we couldn't regroup, that's what really hurt us. If that had occurred in the first half, we probably could've recovered better."
On Saturday, a 12-point lead turned into as much as a nine-point deficit and though the Griffins battled, they couldn't get it back under six during the closing moments.
Together, the Falcons (23-9) will always hold the distinction of finishing with the final league trophy, a fact not lost on McDonald.
"We came here in '08, we had never won a game down here since I took the women's job," McDonald said. "We had been pounded and wiped out. Then we won in '08 and that was certainly very exciting. Kaitlin's freshman year was special in 2010, but honestly I feel like this one is the best one of all.
"Perhaps it's because I'm a West Virginia kid; I'm from Romney and I have a great love for state and the West Virginia Conference. So maybe there's a little something in my heart for winning last West Virginia Conference tournament. I think that might be something that means quite a bit to me, personally. It's a special league and quite frankly, I hate to see it go."
Paige Alviani led Seton Hill with 18 points and Gattuso added team highs with eight rebounds and five assists.
Fairmont State and Glenville State, which entered the WVC tournament ranked 12th in the nation but fell to Charleston in the quarterfinals, will each have a week to wait before learning their postseason destinations as NCAA Division II tournament selection will be held next Sunday.
Reach Ryan Pritt at 304-348-7948, ryan.pr...@wvgazette.com, or follow him at twitter.com/RPritt.