The loss halted a five-game win streak for the Red Storm (12-8, 5-4 Big East) and gave the Pirates (12-8, 4-5) their third win in four tries.
Alisha Kebbe led the Johnnies in points with 15, including a trio of 3-pointers, while Maya Singleton grabbed a game-high 12 rebounds. The senior, who ranks in the top five nationally in double-doubles, fell short of that mark with only six points.
Qadashah Hoppie also reached double figures for St. John’s, scoring 11 points.
Facing the conference’s leader in steals per game, the Johnnies won the turnover battle, committing just 16 while forcing 22 Seton Hall miscues.
St. John’s will return to action on Friday with a trip to Omaha for a showdown with Creighton at 8 p.m.