Shenandoah (21-6, 9-3 ODAC) scored two runs in the seventh and one in the eighth to take a three-run lead over the Eagles (16-13-1, 5-9), but had to hold on in the ninth.
Snider, coming on for fellow reliever Jonathan Dance with runners on second and third and nobody out, issued a base on balls to his first batter before inducing a fielder's choice that cut down the lead runner at the plate.
Hornets skipper Kevin Anderson then turned to Ritenour, and the junior closer got Eagles centerfielder Jacob Grabeel to ground into a game-ending 4-6-3 double play.
Dance, who came on for starter Michael Bugonowicz midway through the eighth, worked through a two-on, one-out jam of his own with flyouts to center and left.
Leftfielder Nick Goode made an over-the-shoulder grab on the two out smash into the left-center gap to end the BC threat.
Bugonowicz (4-1) went 7 1/3 innings and gave up three runs on eight hits while striking out eight.
Keegan Woolford drove in what proved to be the game-winning run on an infield hit with one out in the seventh. With Tristan Baker on third thanks to a Robert Marcelle single and a wild pitch, Woolford legged out a dribbler down the third base line to put SU up 4-3.
Marcelle then came home one pitch later on a Luke Nussman sacrifice fly to the warning track in right.
Nussman and Marcelle both had two hits and two RBI on the day. Marcelle's two RBI came on a one out single to center in the third. Nussman drove Marcelle in with a single up the middle to cap the three-run third.
Henry Delavergne drove in the final run with a single to left center in the eighth.
Three of the Hornets six runs were unearned.
Shenandoah is back on the diamond at Elizabethtown in a 3:30 non-league contest Wednesday afternoon.