The hosts trailed by 10 points at half-time but rallied in the final quarter against the struggling Aviva Premiership side to score 14 unanswered points and claim a 17-13 triumph.
Tongan number eight Opeti Fonua was a constant thorn in the Dragons’ side and was largely responsible for the Exiles taking a 3-0 lead, thanks to the boot of Tristan Roberts.
The Dragons levelled through Tom Prydie but were behind again when wing Nick Scott exploited some shocking defence to score a try in the 18th minute. But when Nic Reynolds was yellow-carded for an illegal tackle, the Dragons had an opportunity to assert their authority on Welsh.
But they could not take advantage as the 14-men added a further three points without reply by the time Reynolds returned and led 13-3 at half time.
In the final 20 minutes the Dragons upped the tempo and a try from Richie Rees brought them back into contention.
Tom Prydie kicked the conversion before racing down the wing to score a try of his own, which he kicked, to put his team four points in front. Yellow cards for Tristan Roberts and Ian Gough meant an untidy finish to a poor game and the Dragons know they will have to improve before travelling to Leinster in the Pro 12 next Sunday.
