Shenandoah (6-6, 2-3 ODAC) erased a one-goal halftime deficit with a strong third quarter before clinching the win with a dominating final 15 minutes.
Leading 10-8 thanks to five-goal third, SU scored seven of the game's eight fourth quarter goals to pull away from the Marlins (3-9, 1-5).
VWU cut its deficit to just one, 10-9 on a Joe Couture goal 34 seconds into the final stanza, but it was all Hornets following that tally.
Michael Brooks, who led the victors with four goals and three assists for seven points, started the game-ending run with an unassisted goal at 11:31.
Hornets goalkeeper Jason Simpson had a career-high 19 saves on the day and made seven of those stops in the third quarter.
Shenandoah outshot the Marlins 43-40, had a 39-28 edge in groundballs and won 18-of-29 faceoffs.
In addition to Brooks' four goals and three assists, Weaver had four goals and one assist and Schott two goals and two assists.
Goss and Orlando Levins each added two goals.