Akeem Richmond also scored 16 points.
The Pirates' 3-0 start is their first since the 2008-09 season, and Kemp has scored in double figures in all three games.
Miguel shot 7 of 12 from the field, including 3 of 5 from beyond the arc, and he made 7 of 8 free throws. Kemp was 8 of 10 on foul shots as the Pirates outscored the Spartans 21-10 from the free-throw line.
East Carolina trailed 62-59 with 8:06 left, but a dunk by Kemp and Richmond's 3-pointer put the Pirates ahead to stay.