Pointer was 6 of 9 from the field and 7 of 8 from the free throw line.
D'Angelo Harrison had 15 points and is now three away from becoming the third player in St. John's history to join the 2,000-point club.
St. John's built a 44-32 lead at halftime behind 11 points apiece from Greene and Pointer.
Kris Dunn led Providence (16-6, 6-3) with 23 points.
Providence went on a 13-8 spurt, with eight points by Dunn, to cut its deficit to 55-49. LaDontae Henton pulled the Friars within two points, but St. John's went on an 8-0 run, highlighted by two 3-pointers by Harrison, to pull away.