Florida Atlantic (10-16, 5-6 Conference-USA) led 16-15 with 4:48 left in the first after Pablo Bertone made a 3-pointer. The Owls wouldn't score another point before the break, however, and UTSA (8-16, 4-7) closed the first half on a 13-0 run to go ahead for good.
The Owls tried to ignite a run with 4 minutes left to play, and even got as close as four points, but Agusi knocked down eight-straight points for the Roadrunners to squash any chance of a comeback.
Jordan Sims made 14 points for the Roadrunners, and Edrico McGregor added 10 rebounds.
Bertone led Florida Atlantic with 16 points.