Tyler Melville added 15 points for the Big Green (6-13, 2-3), as the trio made 20 of 31 field goals. Mitola was 4 of 5 and Melville 3 of 4 from 3-point range.
Dartmouth finished 7 of 15 from 3-point range to 3 of 20 for the Lions (9-10, 1-4).
A 14-2 Columbia run erased an 11-point Dartmouth second-half lead. John Daniels' dunk with 2:41 remaining put the Lions ahead for the last time, 54-52.
Mitola responded with a free throw, a layup and a 3-pointer for Dartmouth.
Gonzaga has signed California transfer Jordan Mathews to a financial aid agreement for the 2016-17 season.
Coach Gilmore on CWS win: 'It's indescribable' Coastal Carolina head coach Gary Gilmore reflects on his 21 years as head coach and is proud of how far the program has come.
Two late June events provided a great start on the 2020 class and a look at some new 2019 talent.