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.
Tshiebwe's relationship with Sagaba Konate helped West Virginia land a player who had his pick of high-major offers.
SEC Network's Marcus Spears joins Rocky Top Tip-Off to be a special guest in judging Tennessee's dunk contest.
Oscar Tshiebwe, a 6-foot-9 center out of Pennsylvania who averaged 21.3 points and 11.7 rebounds on the Adidas Gauntlet circuit, chose WVU over Kentucky, Baylor and Illinois.