The Billikens (6-6) trailed for most of the first half and went into the intermission down 38-30. They opened the second half with an 18-3 run and never trailed again.
The Camels (5-6) used an 8-1 run to close within 60-56 on Chris Clemons' free throws with 3:34 left, but Goodwin stopped the momentum with a 3-point play and Saint Louis made 9 of 12 free throws to go with Davell Roby's layup to hold on to the lead.
Johnson made all three of his 3-point attempts, all six of his free throws and 4 of 6 overall from the field for Saint Louis. Hasahn French added 11 points and 12 rebounds.
Chris Clemons had 28 points and Marcus Burk had 20, accounting for all but 18 of the Camels' points.
Williams advocates for Zion to sit out the rest of season
Jay Williams notes the amount of money Zion Williamson could potentially lose and previous knee injuries as a reason for him to sit out the remainder of the season.
Behind-the-scenes game-day jobs you never knew existed
The 93-year-old Spurs lifer. The ice crew in Tampa upholding the work of a sick colleague. The groundskeeper fighting the Buffalo snow. What really happens on game day?
Duke moving forward after Zion injury, loss to UNC
Coach Mike Krzyzewski and Duke get ready for Syracuse with question marks around Zion Williamson's health.