A last-gasp try from Wyn Jones fired the Dragons to a sensational 36-31 victory over Stade Francais in Paris.
With the clock in the red, Harrison Keddie surged down the touchline before slipping an inside pass to Morgan Lloyd. The scrum-half was hauled down just short, but after a series of close-range drives, former Wales prop Jones crashed over to clinch a famous victory for the Men of Gwent.
It capped a thrilling encounter in which the Dragons looked in complete control at 17-0, only to be pegged back by a resurgent Stade Francais, forcing them to dig deep and ultimately win the contest all over again.
The Dragons will face the winner of Pau v Zebre away from home in the quarter-finals of the EPCR Challenge Cup, but based on today's performance they will fancy their chances of reaching the last four.
Tries from Angus O'Brien, Brodie Coghlan, Chris Coleman, Elliot Dee and Jones helped seal a famous victory. O'Brien and Tinus de Beer also contributed 11 points from the kicking tee.
Setareki Turagacoke, Samuel Ezeala (twice) and Yoan Tanga scored tries for the hosts.
The Dragons made a dream start, racing into a 17-0 lead after a mere 21 minutes. After winning a penalty at the scrum, the Dragons had a lineout deep in the Stade Francais 22.
The Welsh club executed a well-worked starter play off the back of the lineout, with a long pass from Tinus de Beer putting O'Brien through a large hole to score the opening try, which he converted himself.
Tiatia's side was in the ascendancy, dominating the physical aspect of the game with their set-piece on top.
After succeeding in pushing the hosts back into their own 22, the Dragons set up a well-worked driving lineout which pushed the Parisians backwards at a rate of knots for Coghlan to touch down from short range, with O'Brien adding the extras.
But Stade Francais quickly snapped back into life and put the Welsh club under severe pressure in the second quarter of the game.
They had two tries disallowed by the TMO; the first came after No 8 Yoan Tanga tapped the ball into his own player on the way to the line, and the second when Pierre Henri-Azagoh grounded the ball short of the line.
But Stade finally turned pressure into points when Ezeala touched down out wide after some slick handling. Ezeala claimed a second try shortly after when he hit a wicked angle to score, meaning the Dragons held a slender 17-14 lead at the interval.
The hosts started the second half strongly and took the lead for the first time in the game when Tanga sliced open the Dragons' defence to score.
But the Dragons refused to throw in the towel and, after a period of sustained pressure, Chris Coleman powered over the line, with O'Brien adding the extras to level the scores.
Stade hit back with Ezeala claiming his second try, but the Dragons responded well yet again with Dee touching down off the back of another well-worked maul.
O'Brien missed both the conversion and a late penalty, but there were jubilant scenes in the Dragons coaching box when Jones claimed the match-winning try.
Stade Francais: Ibo; Laloi, Marchant, Ezeala, Etien; Foursans-Bourdette, Abadie; Iscaro, Peyresblanques, Lux, Azagoh, Turagacoke, Scelzo, Chapuis (capt), Tanga.
Replacements: Garcia Albo, Paiva, P Alo-Emile, Huguet, Briatte, Motassi, Vili, Henry.
Dragons: O'Brien (co-capt); Richards, Inisi, Owen, Dyer; de Beer, Armstrong; Martinez, Coghlan, Coleman, Douglas, Carter (co-capt), Woodman, Young, Wainwright.
Replacements: Dee, W Jones, James, S Davies, Keddie, M Lloyd, Paea, Anderson.
Referee: Morne Ferreira (South Africa)
Assistant Referees: Griffin Colby & Christopher Allison (South Africa)
TMO: Marius Jonker (South Africa)
