Martinez passed for 155 yards with an interception and also picked up 80 yards on the ground for Nebraska (1-0), which claimed its 27th straight win on opening day.
Ameer Abdullah racked up 114 rushing yards on 19 carries and Imani Cross added 105 more with two touchdowns for the Cornhuskers.
The Cowboys (0-1) lost despite a great game from Brett Smith, who threw for a career-high 383 yards and four touchdowns, and amassed 92 rushing yards on eight carries.
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