Munster's top-four prospects took a blow after they were stunned 17-6 by the Cardiff Blues at Musgrave Park in the Pro12 on Saturday.
Ronan O'Gara and Rhys Patchell traded a penalty each as the teams went into the break on level terms.
Although O'Gara added a second three-pointer in the second half, converted tries from Owen Williams and Robin Copeland sealed a shock result for the Blues.
Looking to build on their impressive victory over league leaders Ulster last week, the hosts made the early running. However, Cardiff proved dangerous on the counter-attack and, after a brief foray into the opposition 22, Patchell kicked them into the lead.
Copeland then made an impressive break as the visitors continued to threaten, but order was restored when O'Gara levelled, rewarding their period of pressure.
Although Munster finished the half on top with centre James Downey prominent, the game remained finely poised at 3-3 at half-time.
It was the Blues that made the first inroads in the second period when they touched down for the first try of the match.
Wales' centre Jamie Roberts came on to Patchell's pass and his inside ball to Williams saw the winger scamper away for a well-worked score.
The Irish province's fly-half immediately reduced the deficit with a three-pointer, but they were struggling to consistently test the away side's vastly improved defence.
Cardiff had a chance to seal the win but Roberts' off-load was forward. However, they finally secured a superb result when Copeland latched on to a loose ball and crossed the whitewash.
Pens: O'Gara 2
For Cardiff Blues:
Tries: O. Williams, Copeland
Cons: Patchell 2
Munster: 15 Felix Jones, 14 Doug Howlett (c), 13 Keith Earls, 12 James Downey, 11 Johne Murphy, 10 Ronan O'Gara, 9 Conor Murray, 8 James Coughlan, 7 Sean Dougall, 6 Tommy O'Donnell, 5 Donnacha Ryan, 4 Dave Foley, 3 Stephen Archer, 2 Mike Sherry, 1 David Kilcoyne.
Replacements: 16 Sean Henry, 17 Wian du Preez, 18 BJ Botha, 19 Billy Holland, 20 CJ Stander, 21 Duncan Williams, 22 Ian Keatley, 23 Casey Laulala.
Cardiff Blues: 15 Jason Tovey, 14 Owen Williams, 13 Richard Smith, 12 Jamie Roberts, 11 Harry Robinson, 10 Rhys Patchell, 9 Lewis Jones, 8 Robin Copeland, 7 Sam Warburton, 6 Josh Navidi, 5 Lou Reed, 4 Bradley Davies, 3 Benoit Bourrust, 2 Rhys Williams, 1 Sam Hobbs.
Replacements: 16 Kristian Dacey, 17 Paetru Tamba, 18 Scott Andrews, 19 James Down, 20 Luke Hamilton, 21 Alex Walker, 22 Ceri Sweeney, 23 Leigh Halfpenny.
Referee: Nigel Owens
Assistant Referees: Michael Black (Ireland), John Carvill (Ireland)
Television match official: Jude Quinn (Ireland)