The third-seeded Hornets (28-11) swept the Tigers (17-19-2) with a 5-0 win Saturday and the one-run victory Monday.
SU advances to a 7:30 game Friday night versus second-seeded Roanoke at Haley Field at Salem Memorial Ballpark in Salem, Virginia.
Shenandoah scored the winning run in the top of the seventh (SU was playing as the visitor by tournament rule) as Robert Marcelle opened the frame with a double down the left field line and eventually scored on Jamie Naill's sacrifice fly into left center.
Matt Barnes (3-1), who came on in the fourth, held H-SC at bay through the seventh before allowing a leadoff single in the eighth.
Closer Gerard DePhillips then came on and shut the door on the Tigers. In the eighth, he induced an inning-ending 5-4-3 double play and had a huge pickoff at second base in the ninth to record his ODAC and school-record-tying 11th save.
Designated hitter Matthew Spagnolo led off the H-SC ninth with a double into the left field corner but the Tigers lost all of that momentum as DePhillips picked off pinch runner Mack Reese before delivering his next pitch.
H-SC followed with two hits only to see DePhillips record a pair of strikeouts to end the contest.
DePhillips ties the set by Tyler Hott '17 in Hott's senior year.
After the Hornets scored three runs on four hits in the top of the first, Hampden-Sydney took advantage of a pair of Shenandoah errors to score three runs on four hits in the second.
The two teams traded runs in the third with H-SC again scoring an unearned run.
The Tigers took the lead in with two runs in the fourth, chasing Hornets starter Reeves Lowry before Shenandoah returned the favor in the fifth. SU scored its two runs on four hits and ended the day for H-SC starter Jonathan Triesler.
Baker finished the day 3-for-4, moving into the third spot all-time in hits at Shenandoah in the process, with Ritter, Marcelle, Thompson and Luke Nussman all getting two hits.
Barnes allowed just the one hit in 3 1/3 innings of relief.
Shenandoah advances to the ODAC Championship Tournament in Salem, Virginia. The four-team, double-elimination tourney begins on Friday with No. 1 Randolph-Macon taking on fourth-seeded Virginia Wesleyan at 4 p.m. Shenandoah meets second-seeded Roanoke at 7:30 and all games will be played at Haley Field at Salem Memorial Ballpark in Salem.