Replacement flanker Ben White went over seven minutes from time as the Blues came within inches of pulling off an impressive comeback at Rodney Parade pulling the final score to 14-13.
The normally sure footed former All Black Blair saw his fourth kick of the game sail wide to send the Dragons up to eighth in the Magners League. A successful conversion would have been heartbreaking for the Dragons who led 14-5 after an hour following three penalties by Ceri Sweeney and an early try from Nathan Brew before Xavier Rush's first-half reply for the Blues.
The Dragons were forced to dig deep after they were reduced to fourteen men for the final ten minutes when centre Paul Emerick was sent to the sin bin and the Blues used their replacements to greater effect as the heavens opened.
Chris Czekaj exploited the advantage, bursting through midfield, before replacements Bradley Davies and White combined for the late try, only for Blair to pull his kick.
A typically bruising local derby got off to a flying start when Gareth Cooper stepped on the gas to produce the game's opening try. Blair had just missed the chance to equalise after Sweeney's first penalty when Cooper sped forward from Colin Charvis's turnover before kicking ahead for Brew to score on seventeen minutes.
Brew hobbled off before half time with an ankle injury soon after Rush had finally galvanised the Blues, driving over from close range.
Yet it was a rare attack for the Blues, who sorely missed the suspended Martyn Williams as they were forced to live off scraps. Sweeney nosed the Dragons further ahead but had to hold out against the elements as the Blues stormed back.