Sophomore, Castrillon put Holy Cross on the board at 31:00. The Crusaders were able to hold the lead the rest of the half and through the first part of the second half.
Delmiro Fernandez tied the game off a Ross Cardinell assist at 68:13.
The second half proved to be physical with both teams recording 15 fouls and two yellow cards each.
Liam Welsh scored the winning goal late in the game off a Michael Battiste assist to lead Siena to their first win of the season.
Siena improves to 1-2-1 and Holy Cross falls to 3-1-0 overall.
The Crusaders travel to Sacred Heart Tuesday at 4:00 p.m.