Sandora Irvin added 16 points and seven rebounds and Ebony Shaw
scored 10 for the Lady Frogs (3-0).
Julie Sullivan had a chance to tie it at 75 for the Cougars
(2-2) with 30 seconds left but went 1-of-2 from the line.
TCU shot 49 percent (27-for-55) from the field and forced BYU
into 20 turnovers.
Ambrosia Anderson scored a career-high 21 points and grabbed 11
rebounds to lead BYU, which was 20-for-53 from the field.
BYU cut TCU's lead to 53-47 five minutes into the second half.
Irvin and Pack then scored TCU's next 11 points to give the Lady
Frogs their biggest lead of the game at 64-49 with 11:56 left.
The Cougars countered with a 12-2 run to cut TCU's lead to 66-61
following a basket by Danielle Cheesman with 6:50 left.
TCU led 75-73 with 56 seconds left after a layup by Anderson,
but Pack and Shaw each hit two free throws to preserve the win.