Texas, 6-1-1 overall and 3-0 in the Southwest Conference, destroyed by defensive pressure in losses to the Red Raiders the past two years, scored on four of its first seven possessions to take a 28-0 halftime lead.
Three of the scoring drives took less than two minutes.
Texas Tech (5-3, 2-2) lived up to its blitzing reputation, but the Red Raiders were kept completely off balance by the Longhorns, who mixed the pass with the running of Mitchell and Ricky Williams in rolling up 304 first-half yards.
Mitchell ran 11 times for 105 yards, including touchdown runs of 32, six and 36 yards. Williams ran 15 times for 113 yards.
Texas Christian 19, Southern Methodist 16--Rick LaFavers intercepted SMU's two-point conversion attempt late in the fourth quarter and returned it 99 yards to give TCU two points and preserve an SWC victory at Fort Worth.
SMU pulled within 17-16 on a one-yard touchdown run by freshman quarterback Derek Canine. The Mustangs, who had blown a 10-0 lead, opted for a two-point conversion.
Canine threw to his right, aiming for Vaughn Dickerson, but LaFavers stepped in front, caught it and turned upfield for TCU's first defensive conversion since the rule went into effect in 1990.
The return gave TCU (6-2, 3-1), its fifth victory in six games and kept the Horned Frogs alive in the race for the title in this, the final year of the SWC.
For SMU (1-8, 0-5), the failure to convert meant an eighth consecutive defeat, longest among major colleges, and kept the Mustangs winless in their last 18 SWC games. Vanderbilt snapped the previous longest streak at nine games by winning on Saturday.
Fumbles by Canine, one at the goal line, killed SMU drives in the first and fourth quarters.