The European champions jumped out to an early 2-0 lead after Cameroon striker Eto'o chipped a pass to forward Goran Pandev who opened the scoring in the 13th minute.
Declan Danaher was sin-binned for taking out Josh Lewsey off the ball and Wasps increased their lead with a penalty after Geraghty's misplaced pass led to panic in the Irish defence.