Anderson finished with 17 points, Williams had 16, and Jones added 11 for Robert Morris (8-4), which hit 13 of 27 attempts from 3-point range.
There were seven lead changes and four ties over the first 6 minutes of the first half before Jones broke open a 16-all game with a 3-pointer. The Colonials led by at least two the rest of the half and took a 40-34 lead into intermission.
Louisiana-Lafayette (4-8) rallied to take a 52-47 lead in the second half but Williams, Anderson, and Russell Johnson hit consecutive 3-pointers to put Robert Morris up for good, 56-52, with 8:02 left to play.
Mbamalu Bryant led Louisiana-Lafayette with 21, Elfrid Payton had 19 but the Ragin' Cajuns hit just 8 of 17 free throws.
ESPN's Dan Dakich joins The Paul Finebaum Show to discuss the SEC's presence in the NBA Draft.
Ted Kapita was the top-rated recruit from West Virginia in the class of 2015 and recently played at DME Academy in Florida.
With the Suns drafting Tyler Ulis, they now have five guards on their roster who attended Kentucky.