The victory puts the Brewers at 5-1 with a game remaining at Harwick on Tuesday, December 6 before break.
Hannay's career highs in points and rebounds came in only 16 minutes.
The Brewers got another solid effort from junior center William Kieffer (Chappaqua, NY), who scored 19 points, grabbed 8 rebounds on a 7-for-10 night from the floor. Kieffer added three assists and was 5-for-5 from the free throw line.
Sophomore guard Danny Forcella (Falmouth, ME) notched a career high in points as well, tallying 18 on the evening on a perfect 5 for 5 from 3-point range. For the game, Vassar shot 56.5 percent from the floor and 53.6 percent from 3-point distance.
Fellow sophomores Tyson Brazell (Salt Lake City, UT) scored 11 points and Lawrence Avitabile (Southington, CT) added 10 points.
Vassar, which outrebounded Purchase 41-16, overcame 15 first half turnovers in victory. The Brewers held a 44-35 lead at intermission.