All of Falker's points came in the second half and overtime, and he made five of the Salukis' 12 overtime points. Mullins made 15 of his points off of 3-pointers and helped bring Southern Illinois (14-12, 9-6) back from an eight-point deficit in the second half.
The Shockers (10-16, 3-12) struggled in overtime, making just 2-of-8 from the free-throw line.
Wichita State led for most of the first half, thanks to Matt Braeuer, who scored 17 of his game-high 23 points in the half. But a late 12-4 run by Southern Illinois gave the Salukis a 29-25 lead. The Shockers answered back, scoring six straight points and led 31-29 at halftime.
With seven minutes to go in the second half, Wichita State had its largest lead of the night, at 53-45, but that's when Mullins got hot. The senior guard scored 10 of the team's next 12 points and cut the Salukis' deficit to two with two minutes to play.
Southern Illinois was down one with under a minute to go when Falker missed three attempts from under the basket. After being fouled on the last attempt, Falker made two free throws to give Southern Illinois a 60-59 lead with 30 seconds left.
P.J. Couisnard, who had 17 points for Wichita State, was fouled on the Shockers' ensuing possession and made one free throw to force overtime.
Ramon Clemente had 12 rebounds for Wichita State.