FORT WORTH, Texas (AP) -- While TCU is accustomed to better defensive performances, the third-ranked Horned Frogs should be just fine if they have to keep depending on Trevone Boykin and their high-powered offense.

Boykin threw for 454 yards and five touchdowns, the last a 42-yard strike to Josh Doctson with 6 1/2 minutes left after SMU had gotten within five points, and TCU held on for a 56-37 victory Saturday night.

"We're really just doing what we do. ... We try to score a lot of points," Boykin said. "If the defense gives up 55 points and we score 56, then it's all good with me at the end of the day as long as we win."

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The Heisman hopeful also added a highlight 20-yard touchdown run after he ducked out of a sack before halftime.

While the Frogs rolled up 720 total yards on 71 plays, they gave up 508 yards. SMU even scored 20 consecutive points to get within 42-37 on Chad Hedlund's 32-yard field goal with 8:20 left.

"If you think I'm happy about giving up 500 yards and 37 points, no. But right now, you better enjoy every win you can get," said coach Gary Patterson, who still runs the TCU defense like he did before becoming head coach 15 years ago. "Offensively, they're all great."

The Horned Frogs (3-0) won their 11th consecutive game, a winning streak second only to the 16 in a row by top-ranked defending national champion Ohio State.

TCU was up 42-17 when Boykin threw a 31-yard TD pass to Kolby Listenbee on the first series after halftime before SMU, with its own dual-threat quarterback in Matt Davis, had its surge.

"Obviously it's a frustration for a team that's used historically and is very proud about playing defense," Patterson said. "It may be our job not to win total yardage, but the job to hold them to one less point. If that's what our job is, that's what our job is."

Boykin, who finished fourth in the Heisman Trophy voting last year, completed 21 of 30 passes. His only interception did help the late surge by SMU (1-2), but the senior quarterback made another big throw to Doctson to make sure the Frogs avoided being upset in the Battle for the Iron Skillet.

Doctson had five catches for 171 yards and two touchdowns. Aaron Green ran 21 times for 164 yards with two scores, including a 1-yarder in the final minute.

Davis, who began his college career as a freshman at Texas A&M and never played over Johnny Manziel, was 17-of-31 passing for 330 yards with a touchdown, and ran 17 times for 62 yards and two scores.

Both of Davis' TD runs came in a 79-second span of the third quarter. He scored on a 4-yarder and added a 1-yard plunge three plays after Horace Richardson intercepted Boykin's pass.

SMU, playing its first road game for new coach Chad Morris, was within 42-34 when Hedlund kicked a 21-yard field goal on the final play of the third quarter.

After Green was stopped on fourth-and-1 at the TCU 23 on the ensuing possession, Davis scrambled 19 yards and then threw a 42-yard pass to freshman Cortland Sutton, who made a tremendous catch at the 15 between two defenders called for pass interference. The Mustangs then lost yards on three plays in a row before Hedlund last field goal.

The Mustangs opened the season at home with a 56-21 to fifth-ranked Baylor, which last year shared the Big 12 title with TCU. They beat North Texas.

TCU was up 28-10 just before halftime when Boykin had his highlight run, after he was back to pass and suddenly had a defender coming at him. Boykin pulled the ball down, turned his body and ducked while linebacker Nick Horton swiped over his head, then spun back around and took off for a 20-yard touchdown.

When SMU freshman Xavier Jones scored on a 2-yard run just more than 3 minutes into the game, TCU trailed for the first time this season.