The Mustangs outscored the Knights 10-0 over the final two minutes as sophomore
Jaylah King scored seven of her game-high 21 over that span.
Qandace Samuels, the game's Most Valuable Player, ended with 20 points and 12 rebounds.
The Knights led 46-38 at the start of the fourth quarter but saw the edge trimmed to 53-47 on a pair of Samuels free throws with 2:37 left.

Jaylah King scored 21 as No. 2 Bishop McNamara upset No. 1 Ontario Christian 57-55 on Friday at the Hoophall Classic. (FILE PHOTO: Darin Sicurello)
Smith bumped the lead back to eight for Ontario Christian with blow-by layup at the 2:06 mark. But that's the last time the Knights would score.
Tegan Primus hit the first of two free throws as Samuels grabbed an offensive board and King converted to cut the Ontario Christian lead to 55-50. Following a timeout,
Dani Robinson's missed 3-pointer led to a fast break where King drove to the bucket and scored with 42 seconds left. A steal led to two King free throws with 33.9 left as Bishop McNamara trailed 55-54.
The swarming McNamara defense again swiped the ball as Samuels hit down low for the go-ahead bucket with 1.2 seconds remaining before King added one of two freebies for the final margin.
The victory by Bishop McNamara (13-2) adds another marquee win to its resume. They beat then-No. 1 Archbishop Mitty in the semifinals of the Nike Tournament of Champions before Christmas and backed that up with a tournament title victory over Long Island Lutheran.
The Mustangs erased multiple deficits of nine or more as they trailed 22-13 early in the second quarter and then 51-42 midway through the final stanza.