Sin-binned Adam Black returned to the field to score the last-minute try that allowed Percy Montgomery to kick the Dragons the win over the Warriors
Final score 20-18, and the kick could prove crucial in the final Celtic calculation. The win means the Dragons keep in touch with Ulster and the Scarlets at the top of the table as the race for the title moves into the home straight.
The Warriors led for most of the match despite having two men yellow-carded and they played with 14 after flanker Maama Molitika was sent off in the 69th minute.
The first half was disrupted by a succession of off-the-ball incidents and brawls with both sides at fault. Referee Alan Lewis eventually had enough and sinbinned props Adam Black and Phil Booth.
Barely two minutes later Warriors lock Nathan Budgett followed them into the sinbin.
The tackling of both sides was ferocious and the only scores of the half were two penalties for the Warriors by Neil Jenkins and two for the Dragons by Montgomery.
Jenkins nosed the 13-man Warriors in front with a penalty before Gareth Baber charged down a Kevin Morgan kick for Jason Forster to get the first try of the game.
Three more Jenkins penalties put the Warriors 18-13 ahead but the dismissal of Molitika was the turning point.
The Dragons mounted a last desperate attack in the final minute and Black eventually forced his way over after a succession of rucks near the Warriors line and Montgomery kicked the crucial conversion in an intense watched by 4,366 spectators.