Longford Town 1 Waterford United 0
Stephen Kelly put Longford Town into the first Cup Final in their 77 year history with a late penalty.
Blues skipper Brendan Rea was adjudged to have handled a long ball into the area under pressure from Shay Zellor in the 76th minute.
And Kelly had the 6,000 crowd in ecstasy as he sent Anthony Fennelly in the Blues' goal the wrong way from the spot.
Longofrd now meet Bohemians in the final at Tolka Park on May 13.
It was tough on First Division Waterford who played the better football.
But chances to Alan Kirby and Kevin Whittle were missed as Blues' season ended in disappointment.