Sophomore Michael Crabtree was Harrell's favorite target, catching eight passes for 164 yards and three touchdowns for the Red Raiders (3-0).
Baron Batch led the winner's ground game with 99 yards and a TD on 10 carries. Daniel Charbonnet had three interceptions for Texas Tech.
Bo Levi Mitchell had five interceptions on 13-of-24 passing for 155 yards for SMU (1-2). Emmanuel Sanders had eight catches for 125 yards for the Mustangs, who were outgained 693-274.