The Salukis (11-15, 4-11 Missouri Valley), who snapped a seven-game losing streak in the series, scored the game's first 10 points, never trailed and shot 51.2 percent (22 of 43) from the floor.
Missouri State trailed by nine points at intermission but got within 40-38 midway through the second half. But the Bears then went scoreless for a stretch of 6:01, enabling Southern Illinois to take permanent control.
Anthony Beane scored five points and T.J. Lindsay hit a 3-pointer during a 10-0 run. Beane's three-point play made the score 50-38 with five minutes remaining, and Missouri State got no closer than six points the rest of the way.
Officials: North Carolina must show proof of discrimination-free zone, or lose NCAA tournament games
North Carolina must prove to the NCAA that its host arenas will provide a discrimination-free zone or risk losing NCAA tournament games in 2017 and 2018, multiple officials told ESPN.
Jalen Rose and David Jacoby examine the new NCAA draft rule and consider how it would have affected "The Fab Five."
Florida and Duke will meet on Dec. 6 in the Jimmy V Classic at Madison Square Garden as one of two high-profile games to help raise funds for cancer research.