With one out, Eagles first baseman Brendan Powell reached on an error and was sacrificed to second.
Shenandoah (13-5, 3-3 ODAC) skipper Kevin Anderson turned to closer Phillip Morse at this point, and after a hit batsman, Morse appeared to get out of it by inducing a Brandon Poole comebacker to the mound.
Unfortunately for the home fans, Morse' throw to first sailed wide, allowing both Powell and Chris King to score and Poole to reach third.
Catcher Hunter Hensley then made it 3-0 with an RBI single to left center. Hensley's hit was just the fourth of the day for the Eagles (13-8, 4-3).
In the bottom of the frame, Steven Woerner sent SU down in order to clinch the victory.
The defensive miscues ruined an excellent start by sophomore Colin Morse, who struck out 10 and scattered two hits and three walks in 7.0 innings.
Ryan Mossman (2-1) pitched out of a 1st-and-3rd, no outs jam in the eighth with a strikeout and a double play, but took the loss after Powell reached on that one-out error by Hornets shortstop John Wilt.
Ryan Leake (2-2) pitched the first eight innings for BC and earned the win after scattering four hits and four walks against one strikeout.
Shenandoah is back in action at home on Thursday at 3:00 in a non-league game against Mount Aloysius.