DALLAS (AP) -- Trevone Boykin threw for four touchdowns and ran for two others Saturday and TCU defeated SMU 56-0 in the Plains Capital Bank Battle for the Iron Skillet.

Boykin threw scoring passes of 28 and 7 yards to Deante Gray, 6 yards to Josh Doctson and 10 yards to Desmon White. He ran for touchdowns of 27 and 8 yards.

SMU (0-4) failed to score for the second time this season. The Mustangs drove to TCU's 3-yard line in the waning seconds, and reserve quarterback Matt Davis was sacked on the final play.

Mustangs quarterback Garrett Krstich made his first career start, the team's third starter at the position this season. Fourth-string when the season began, Krstich was 14 for 30 for 142 yards, one interception and was sacked seven times.

SMU appeared to score late in the half on a 36-yard reception by Daruis Joseph during which Joseph fell backward onto TCU cornerback Ranthony Texada at the Horned Frogs' 30, rolled off and ran into the end zone. A review of the play revealed Joseph's left elbow touched the turf after he rolled off Texada.

The Mustangs were also stopped on fourth-and-goal at TCU's 1-yard line midway through the second quarter when Horned Frogs defensive end James McFarland broke up a Krstich rollout pass into the end zone intended for Joseph.

The TCU drive ending with Catalon's score was kept alive when SMU's Cameron Smith was assessed a 15-yard personal foul for continuing to play during a third-down stop after his helmet came off.

The Mustangs' defense held TCU on fourth-and-goal at the 2 late in the SMU's Derek Longoria blocked a 26-yard field goal attempt by Jaden Oberkrom midway through the fourth quarter.

SMU travels to Greenville, N.C. next Saturday to take on No. 23/24 East Carolina. Kickoff is to be determined.