However, Munster, fresh from a training camp in Lanzarote, hit back in typically dogged fashion to extend their unbeaten home run to 15 matches.
The 21-year-old Deasy was making only his second league appearance and was introduced, in place of dead leg victim Warwick, just as Edinburgh seized the early initiative, with out-half Blair sending busy hooker Kelly through a midfield gap.
Rob Moffat's men looked the more threatening in open play, the injuries and a malfunctioning lineout did little for Munster's confidence and a Blair drop goal deservedly sent Edinburgh in front.
The hosts responded quickly and Ian Dowling was held up just metres out before fit-again prop Marcus Horan burrowed over from close range, crowning his first provincial start since October with a try.
Deasy pulled his conversion attempt across the posts and Edinburgh, eager for work and protecting the ball well, set up Blair's first successful penalty on 25 minutes.
Deasy crashed a penalty of his own off the post, three minutes later, but he did punish an Edinburgh scrum infringement to move Munster two points clear.
Edinburgh nipped back ahead for half-time though, as a superb line break by Nick De Luca saw them rampage up close to the Munster line, Alan Quinlan was ruled offside and Blair booted his side into a 9-8 lead.
Deasy had the distance but not the accuracy from a long range penalty, just after the break, and an absorbing tie swung back in Edinburgh's favour when flanker Quinlan was sin-binned for a ruck offence and Blair converted the penalty.
Deasy missed an immediate chance to reply but held his nerve to fire over a 57th minute penalty.
Off the restart, Munster snaffled back possession before Deasy broke the Edinburgh line, dangled a chip kick towards the line and took advantage of a favourable bounce - ahead of the covering Mark Robertson - to grab a priceless try.
Deasy failed to convert and Munster had to show some defensive steel to keep Edinburgh at bay in the closing stages, with replacements Simon Webster and Tom Gleeson impressing for their respective sides.
Robertson was thwarted by Mike Sherry with the line in his sight, and with six minutes remaining Lifeimi Mafi saw yellow for taking out support runner De Luca as the visitors probed out wide once again.
But Tony McGahan's charges grabbed two vital turnovers close to their own line as they defiantly held on to take the league points.
|Munster Rugby Score Card|
|Edinburgh Rugby Score Card|