Brickey Rangers shocked Stradbally for the second time in three years at a wet and windy Fraher Field (1-9 to 1-8).
Waterford attacker Tom O'Connell scored 1-5, including the winner two minutes into injury time, to send the Brickeys through to the quarter finals. Stradbally will need to beat Kilmacthomas next weekend to stay in the senior ranks.
"It feels like a big scalp," admitted matchwinner O'Connell. "The season didn't start well for us, a couple of injuries, we were in a bit of disarray. We gave a fair account of ourselves today. We proved to ourselves that we can rattle anyone."
The Reds finished with fourteen men as Liam Fennell was dismissed on two yellow cards. In a dramatic finish, Shane Aherne missed a last gasp free to force extra time. He slipped in the greasy conditions and his shot flew right and wide. A couple of minutes earlier, Tommy Fennell crashed a shot off the crossbar.
The sides were level at the break (1-2 apiece). Paul Tobin found the top corner for Stradbally after 17 minutes. Tom O'Connell hit a thumping shot to the roof of the net on 26 minutes.
Stradbally twice led by three points in the second period. Michael 'Brick' Walsh kicked three off right and left but Brickeys hung in. Five O'Connell points and one apiece from Cormac O'Grady and Sean Ronayne saw them pull off a surprise win.
Former Déise captain Paul Whyte fired four extra time points as Kilrossanty fought off An Rinn 0-15 to 0-8.
Whyte saved a first half penalty from Donie Breathnach before he moved out the field at the end of normal time. From full forward, he scored a point off his left, one off his right, one with the fist and an advanced mark.
Donie Fitzgerald's sixth free left the green and gold 8-6 up entering injury time. He was then dismissed on a black card. Oisín Ó Ceallaigh converted a free and then forced extra time with a huge point from 45 metres on 68 minutes.
Waterford SFC Quarter Finals: Ballinacourty v Kilrossanty, Gaultier v Clashmore/Kinsalebeg, The Nire v Brickey Rangers, Rathgormack v Portlaw
Waterford SFC Relegation Play-Offs: An Rinn v St Saviours, Stradbally v Kilmacthomas