The Blues looked to have snatched the four points after Manoa Vosawai had powered over from close range after Lucas Gonzalez Amorosino had crossed.
But the last minute converted try gave Anthony Foley the perfect return to Guinness PRO12 action. The Munstermen, almost unrecognisable from last weekend’s 14-3 European defeat to Saracens, took an early lead thanks to the boot of JJ Hanrahan after the Blues went off their feet at a ruck.
The early offence sparked a kicking duel between the outside-half and his Welsh counterpart Rhys Patchell, who levelled the scores moments later.
They traded kicks again before Hanrahan got the upper hand. The Arms Park side continued to test referee Marius Mitrea at the ruck and felt the full force of his whistle as Hanrahan landed five from five to make it 15-6.
But the Blues broke-out before the break. Rhys Patchell burst down the unguarded left flank and slipped a perfectly timed pass to Argentina wing Gonzalez-Amorosino, who dived in at the corner.
Munster marched straight back downfield but could only claim a sixth penalty to take the half-time score to 18-14.
The Blues made their set-piece dominance pay when Vosawai crashed over from the base of a five-metre scrum.
Gareth Davies converted to give his side the lead for the first time but Hanrahan levelled.
Davies knocked over a simple penalty before Butler got the better of the scrambling home defence to crash over for the game winning score. Johnny Holland converted to hand Anthony Foley a 28-24 victory.
Â
