Lewis made 5 of 5 field goals and 2 of 2 free throws and Waters had seven assists.
Grambling State (2-25, 0-17), which has lost 20 in a row, trailed just 31-24 at halftime despite making only 9 of 32 (28.1 percent) field goals before the break.
Alabama State caught fire in the second, however, shooting 65.5 percent (19-29) and outscoring the Tigers 44-25.
Remond Brown led Grambling State with 11 points and Richard Freeman added 10 with nine rebounds. A'Torri Shine, the team's leading scoring (13.4 per game), scored a career-low three points on 0-for-9 shooting.