The Lady Raiders (18-11) led from the outset and Grayson County (13-14) was never closer than three points.
The Lady Cougars turned the ball over on four of their first six possessions and Trinity took advantage to score the first eight points of the game.
The lady Cougars finally got on the scoreboard as Molly Beeler hit a shot from just inside the three-point line with 3:30 left in the first period, but Trinity's Sarah McDaniel answered with a three-pointer to put the Lady Raiders up by nine, 11-2.
Grayson County outscor-ed Trinity 9-4 the rest of the first period and trailed by just four, 15-11 heading into the second quarter.
The Trinity defense clamped down at that point, taking the Lady Cougars' Brittany Bird completely out of the game. Grayson County was outscored 10-4 in the second quarter and 14-5 in the third and the game was pretty much over.
First-year Lady Cougar coach Roy King was disappointed after the game.
"It just seemed like we weren't ready to play tonight," he said.
King gave credit to the Trinity coaching staff for some changes that payed off for the Lady Raiders.
"They played much better than they did the other two times we played them" he said. The teams split during the regular season in two very close games.
"They did a couple of things differently tonight. They posted up number 50 (Sarah McDaniel) and she played really well."
McDaniel led all scorers in the game with 16 points, many of them coming on moves in the post. She was joined in double figures by fellow senior Lauren Mattingly with 14 points.
King said he thought the Lady Cougars had a successful season, winning 13 games, more than they had won in the past three seasons combined.
"Like the coach at St. Joseph's said after losing for the first time the other night, you can't judge a team by one game. While we didn't play as well tonight as we have in the past, if these girls keep working like they have, the sky's the limit in the future."
Lee Ann Wood led the Lady Cougars with 10 points. After scoring five points in the first period, Bird finished with seven points.
Beeler had six points and senior Tiffany Clemons, playing her final game in the Grayson County uniform, finished with five.
Cindy Langley scored two points off the bench and Alex Powell had one to complete the scoring.