Tierney was 7-of-10 from the floor and dished out a game-high seven assists. Junior Jackie Dougherty led all scorers with 21 points while freshman Kristy Cramp poured in 17 respectively.
The Griffins (8-2) led 21-8 at the halfway mark of the first stanza and held a 35-22 edge with just under five minutes left before the Bullets whittled down the deficit thanks to a 14-5 run to close the period. GMC led 40-36 at the break.
Gettysburg (6-6) would take its first lead of the game early in the second half, but the Griffins kept it close, never trailing by more than four points.
The Griffins took the lead for good on Tierney's fourth and final three-pointer of the game with 4:35 left, giving GMC a 68-66 advantage.
Cramp sank five treys while Dougherty and junior Rebecca Frederick each pulled down five rebounds apiece.
Jamie Marshall and Jen Bengal scored 20 points each respectively for the Bullets.
Newspaper Box Score Gwynedd-Mercy College vs Gettysburg College 01/04/06 2:00 p.m. at Bream Gym - Gettysburg, PA GWYNEDD-MERCY COLLEGE 88, GETTYSBURG COLLEGE 82 GWYNEDD-MERCY COLLEGE (8-2) Jackie Dougherty 6-12 5-6 21; Karen Tierney 7-10 2-2 20; Kristy Cramp 5-9 2-2 17; Lauren Healy 1-5 5-6 8; Jillian Chiarantona 3-9 1-4 7; Beccie Strohecker 3-10 0-0 6; Bridget Morrin 1-2 0-0 3; Rebecca Frederick 1-1 0-0 2; Allison Gray 1-2 0-0 2; Michelle Sgrillo 1-1 0-0 2; Jess Smith 0-2 0-0 0. Totals 29-63 15-20 88. GETTYSBURG COLLEGE (6-6) Jennifer Bengal 9-17 1-1 20; Jamie Marshall 9-17 1-2 20; Katie Eiden 3-6 11-13 18; Kathryn Reilly 5-16 3-4 13; Amy Tarbell 4-7 1-2 9; Rachel Steel 1-1 0-0 2; Margaret White 0-1 0-0 0; Megan Hartman 0-8 0-0 0. Totals 31-73 17-22 82. Gwynedd-Mercy College......... 40 48 - 88 Gettysburg College............ 36 46 - 82 3-point goals-Gwynedd-Mercy College 15-32 (Kristy Cramp 5-9; Karen Tierney 4-5; Jackie Dougherty 4-6; Lauren Healy 1-3; Bridget Morrin 1-2; Beccie Strohecker 0-3; Jillian Chiarantona 0-4), Gettysburg College 3-11 (Jamie Marshall 1-1; Katie Eiden 1-3; Jennifer Bengal 1-5; Margaret White 0-1; Megan Hartman 0-1). Fouled out--Gwynedd-Mercy College-Ashley Vandiver, Gettysburg College-Jennifer Bengal. Rebounds-Gwynedd-Mercy College 35 (Rebecca Frederick 5; Jackie Dougherty 5), Gettysburg College 48 (Amy Tarbell 10). Assists-Gwynedd-Mercy College 15 (Karen Tierney 7), Gettysburg College 15 (Jennifer Bengal 4). Total fouls-Gwynedd-Mercy College 20, Gettysburg College 20. A-75 Second round of Gettysburg Days Inn Tournament