Williams' 21-yard return came with 2:48 remaining in the game and put the Salukis (5-1, 4-0 Missouri Valley) ahead 27-13.
Pat Grace, who threw for 219 yards and two touchdowns, pulled the Panthers (5-2, 3-1) to within 27-20 with 1:50 left when he connected with D.J. Hord on a 3-yard pass, but Southern Illinois then ran out the clock.
The Salukis, who ended an 11-game losing streak in Cedar Falls, took their first second-half lead with 5:06 remaining on Karim's 1-yard run which broke a 13-13 tie. Steven Morse set up the touchdown, which came on a fourth-down play, when he recovered a fumbled punt at the Northern Iowa 7-yard line.
Derrick Law ran for 123 yards for Northern Iowa.
There's been some buzz that Oregon is starting to slip, but perception doesn't always equal reality when it comes to Power 5 football.
The U.S. Defense Department has said a former Air Force Academy superintendent didn't impede an investigation into allegations of sexual misconduct and drug use by football players.
The USC Trojans claimed victory in 2005 over the Fighting Irish after Reggie Bush controversially helped push Matt Leinart into the end zone for the game-winning touchdown.
The Miami Hurricanes reportedly are looking into whether a player committed an NCAA violation after suspending linebacker Juwon Young on Friday.
In 1998, Brenda Tracy said she was gang-raped by four men, including two Oregon State football players. Since the day of the attack, Tracy has sought a meeting with then-coach Mike Riley. Years later, the two finally meet.
The Sooners will lean on their leader, quarterback Baker Mayfield, to try to make it back to the College Football Playoff in 2016.
|North Dakota State||7-1||13-2|
|South Dakota State||5-3||8-4|