The Blackbirds (9-10, 4-3 Northeast Conference) made 18 of 24 shots in the second half, when they came back from a 33-21 deficit to defeat the Terriers (8-10, 4-3) for the fifth straight time.
Garner scored 17 second-half points, including 10 during a 22-6 run that gave LIU Brooklyn a 62-50 advantage with 4:36 remaining.
Jalen Cannon had 21 points and 10 rebounds for St. Francis.
The series between the two schools, situated slightly over a mile apart, has been billed as the "Battle of Brooklyn" since the 1975-76 season.
The NBA draft is live now (ESPN & WatchESPN), and trade talk is picking up. Chad Ford dishes his latest intel on how the draft will go and which teams will make deals.
Ben Simmons' versatile game bears a strong resemblance to Draymond Green.
Jemele Hill and Michael Smith discuss Tracy McGrady's comments on Ben Simmons' standoffish demeanor. Hill wonders if the "LeBron label" has impacted Simmons for the worse.