Reporting by Matt Keane
Waterford FC remain in a relegation battle following this outcome at the Ryan McBride Brandywell Stadium on Friday night.
Derry City dominated the first half and it came as no surprise when they took the lead on 42 minutes.
Evan McLoughlin who was making his debut for the Candystripes took advantage of extremely poor defending and his weak shot bobbled over Brian Murphy's goal line.
Waterford were left with a mountain to climb when Joe Thompson hammered a magnificent left-footed shot high into the Waterford net seven minutes into the second period.
Jack Stafford struck an upright 15 minutes from full time as the visitors tried to salvage something from the game but that was as good as it got for Marc Bircham's charges.
Next Friday Waterford play Finn Harps in Ballybofey.
Harps lost 3-1 away to Drogheda United on Friday night and they are just seven points ahead of the Blues on the league table.
Elsewhere, Shamrock Rovers returned to the summit of the SSE Airtricity Premier Division last night with a 3-1 win over Dundalk in Tallaght.
Previous leaders St. Pat’s had two men sent off in a 3-2 defeat away to Bohemians.
Sligo Rovers could end the night top of the table if they post a big win away to Longford from 7.30.
