In front of a large crowd and on a perfect surface for football it was Eunans who broke the deadlock on 8 minutes.
Christopher Flanaghan who played from the Republic Under 16 side last week volleyed home a fantastic 20 yard volley into the De La Salle net.
It was a goal fit for any final and gave Eunans under the guidance of Michael Harkin and Gerard Faulkner a great start. And they increased their lead 6 minutes later through a sweetly struck strike from Cathal McDaid.
Into the second half and De La Salle came out fighting and dominated the exchanges but found it hard to breakdown a resolute Eunans rearguard.
Just when it looked like that time was running out for the Waterford men they got a lifeline with a goal with 4 minutes remaining.
But as they pressed for that all important leveller they were hit on the counter attack and conceded a third in stoppage time by substitute Michael Miller who scored into an empty net after an unselfish pass from midfielder Aidan Sweeney.
St Eunans: Shaun Patton, Jordan McBride, Daire McDaid, Sean Hume, Eoin Barrett, Dale Gorman, Aidan Sweeney, Cathal McDaid, Christopher Flanagan, Ryan Rainey, Jason Doherty. Subs: Michael Miller for Doherty. Unused Subs: Ronan Sweeney, Thomas Grant, Luke Bonner, Jason Quinn.