All-Ireland champions Galway, without their sizable Sarsfields contingent, made short work of Dublin in TU Grangegorman.
Dublin were in touching distance, trailing by just 1-9 to 0-5, until Jody Couch was given her marching orders for a second yellow card, nine minutes into the second half.
The Dubs fought valiantly, but it was no surprise that they would begin to tire as a result, and O’Reilly hit the game’s last four points to seal the win for the Tribeswomen.
Dublin face a trip to Offaly on Saturday in their second game.
Senior dubutant Aisling O’Neill from (Castleknock) in action against Galway in Grangegorman Photo: iLivephotos.com