The Aggies (8-3) were in need of a victory after consecutive losses to Mississippi State and Mississippi ruined their shot at the College Football Playoff.
The Roadrunners cut the lead to 3 points early in the second quarter after a one-handed touchdown grab by Josh Stewart. The Aggies then scored the next 13 points, capped by a 47 yard run by Trayveon Williams to make it 23-7 in the third quarter.
"There was a lot of good and a lot of bad," Texas A&M receiver Josh Reynolds said. "There's still a lot of things that we can fix, but ultimately we were moving the ball and scoring."
UTSA (5-6) was led by Jared Johnson, who threw for 186 yards and a touchdown.
Garrett was finally healthy after missing two games and being limited in several others because of a high ankle sprain. Garrett finished with eight tackles, broke up a pass and forced a fumble. Instead of limping as he has been in recent weeks, Garrett was harassing UTSA's two quarterbacks all game.
He further showed his ankle is fine when he batted down a pass in the second quarter and celebrated with a spirited dance. He had another big play in the fourth quarter when he sacked Johnson to force a fumble, which A&M recovered.
"You can see the difference," Texas A&M coach Kevin Sumlin said. "He's a dominant player when he's 100 percent."
Garrett has 8 1/2 sacks this season to give him 32 1/2 for his career, making him the eighth player in Southeastern Conference history with at least 30 career sacks.
"They are phenomenal at the defensive end position," UTSA coach Frank Wilson said. "We tried to do various things to keep them off balance, and assist with blocking with tight ends, but there were a couple of times where Myles Garrett and the other defensive end were able to get beyond us and were disruptive."
Reynolds caught a 16-yard touchdown pass in the first quarter and finished with 93 yards receiving. Williams had 11 carries for 80 yards to leave him 44 yards shy of becoming the first true freshman at the school to rush for 1,000 yards.
UTSA: The Roadrunners, who have had a football team only since 2011, showed they've made a lot of progress by keeping things close. But in the end they just aren't yet on the level to deal with the size and speed of a team like Texas A&M.
TEXAS A&M: The Aggies did what they were supposed to do against a lesser opponent, but Hubenak and the offense will need to be sharper when they return to SEC play next week.
"He's been effective for what we've asked him to do," Sumlin said. "His biggest characteristic right now is he's finding the playmakers."
UTSA: The Roadrunners will look to become bowl eligible for the first time when they host Charlotte on Saturday.
TEXAS A&M: The Aggies face a quick turnaround, wrapping up the regular season Thursday night when they host No. 16 LSU.
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