Lawrence had two targets with over 100 yards receiving, Brian Riley (6 catches 126 yards) and Jonah Hodges (6 catches for 122 yards), who took a screen pass 62 yards for the game-clinching touchdown.
After Hodges' 7-yard dash to the end zone put USD up 21-7 late in the third quarter, Dayton stuck back with two straight touchdowns, including a 31-yard fumble return off a blocked punt.
On the ensuing extra point, the Flyers turned a blocked kick into two-points after Will Willaim found Gus Madden open in the back of the end zone.
Trailing 22-21, the Toreros ended a 70-yard drive with a 1-yard goal line dive by Tevin Heyward. A failed two-point conversion kept USD's regained lead at 27-22 with 4:31 left to play.
Next Saturday the Toreros will travel to Indianapolis to continue their PFL schedule against the Butler Bulldogs.