The loss dropped Xavier to 13-30 overall and 5-10 in Atlantic 10 play while Richmond improved to 23-17 overall, 11-4 A-10.
XU starter Dan Graham suffered the loss after allowing five runs, four earned, on five hits while striking out three over the first 2.1 innings.
Offensively, the Musketeers had six hits, but just two came after the third inning as Xavier posted two runs in the second and one in the third.
Senior Jason Morelli was one of five Musketeer seniors to play their final A-10 game at Hayden Field on Sunday and went 1-for-4 with a 2 RBI double in the second inning.
Junior Jay Johnson had XU's only other extra base hit as he was 1-for-5 with a double and a run scored.
Xavier will take the week off for final exams and return to action on Saturday to begin a three-game series against George Washington in Arlington, Va.