Keifer Sykes added 12 points and five assists for Green Bay (2-1). The Phoenix shot 55.3 percent from the floor compared to 31.9 for East Carolina.
East Carolina (2-2) was led by Terry Whisnant with 23 points on 9-of-17 shooting from the field. The Pirates were out-rebounded 37-23 and gave up 22 second-chance points.
Green Bay's Carrington Love made the game's only field goal through the first 7 minutes. Later, Mays scored seven of Green Bay's next 12 points to extend its lead to 17-3. Prince Williams ended East Carolina's 0 for 13 start with a 3-pointer at the 12:12 mark.
Love hit a 3-pointer to give East Carolina a 21-point lead, its largest of the game, early in the second half.