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.
Gonzaga turns defense into offense with fast-break bucket
Zach Norvell Jr. gets a steal and hustles down the floor to clean up Rui Hachimura's miss, making it 71-65 Bulldogs.
Rudolph gets friendly roll for big and-1
Brandon Rudolph initiates contact with Rui Hachimura, hanging in the air and getting the roll to cut the Bulldogs' lead to 67-65.
Stephen F. Austin rallies to beat Marist 64-60
Jock Hughes and Shannon Bogues combined for 14 points in the final three minutes as Stephen F. Austin came from behind to beat Marist 64-60 in the Basketball Hall of Fame Belfast Classic on Tuesday night.