The Blues almost went a goal up on 13 minutes, but Aaron Drinan failed to connect with a Zac Elbouzedi cross.
But it was Drinan that gave the home side the lead on 18 minutes when a defended Kevin Lynch free kick bounced into his path.
The Ipswich Town loanee showed his quality with another narrow miss in the first minute of the second half.
He bagged his brace on 63 minutes when he got on the end of a JJ Lunney cross.
Advertisement
It finished Waterford FC 2 St. Patrick's Athletic - 0
