Goodwin scored 16 of his points in the first half when Saint Louis took a 35-23 lead. Roby, with just two points in the first half, opened the second with a pair of 3-pointers and added a 3-pointer and a layup in an 8-0 burst for a 23-point lead with 11:38 to go.
Denzel Mahoney, who came in first in the Ohio Valley Conference at 19.2 points per game, finished with 12 on 3-of-9 shooting for the Redhawks (6-7), who shot just 32 percent.
The Billikens (7-6) finished their nonconference schedule with a winning record for the first time since 2014-15.
No. 5 Gonzaga seeks to extend dominance over LMU
Fifth-ranked Gonzaga hasn't lost at home to Loyola Marymount since 1991.
Streaks collide as No. 6 Michigan State goes to Nebraska
Nebraska has won 20 straight games at Pinnacle Bank Arena.
Oklahoma St. dismisses Michael Weathers, Maurice Calloo and Kentrevious Jones
The Oklahoma State basketball team has dismissed three players, including sophomore guard Michael Weathers, who was averaging 9.2 points per game.