Chelf produced 211 yards and two touchdowns passing while adding 88 rushing yards and two more scores on six carries for the Cowboys (7-1, 4-1 Big 12).
Desmond Roland ran the ball 31 times for 96 yards with three scores as OSU reeled off a fourth straight win to jump past the Red Raiders in the conference standings.
Webb Davis completed 45-of-71 pass attempts for 425 yards and two touchdowns for Texas Tech (7-2, 4-2), which fell for a second straight week.
Jace Amaro hauled down 15 passes for 174 yards with a touchdown to pace the Red Raiders' receiving corps.
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'
Jordana Brewster on Paul Walker: 'He was an enormous presence in my life'