12 Dec, 14:42
Prop Cian Healy is expected to miss the start of the 2014 RBS 6 Nations after undergoing surgery on his injured ankle on Wednesday.
Ronan O'Gara added the conversion and cancelled out Jason Tovey's early penalty with one of his own to leave the Blues 10-3 down at the end of a nip and tuck opening 40 minutes.
O'Donnell grabbed his second score but the Blues led 18-17 in the closing stages thanks to tries from Dafydd Hewitt and Lewis Jones.
With two minutes left, the visitors manufactured the match-winning score as O'Gara's short pass inviting the fast-breaking Casey Laulala past Tom James and he darted through to finish off his first league try in Munster colours.
O'Gara's conversion rubbed salt in the Cardiff wounds as Phil Davies' men fell to their sixth successive defeat despite a much improved performance compared to their Dublin drubbing at the hands of Leinster.
Tovey pulled a penalty across the uprights from a difficult position on the left, and the opening minutes were pockmarked by wayward kicking from both Cardiff and Munster.
The Blues showed more in attack early on, Tovey and Tom Williams combining well on a slick break through the middle. An offside decision against Stephen Archer allowed the Cardiff out-half to kick them ahead.
Munster wasted little time in replying. Ian Keatley, lining out at inside centre alongside New Zealander Laulala, was central to the game's first try.
He made a half-break and linked with Luke O'Dea as Munster suddenly burst forward. They retained possession and a high pace as Laulala and Keatley drew in the defenders with the latter's lovely pass releasing O'Donnell for a run in to the left of the posts.
O'Gara converted but found himself in the sin bin shortly afterwards, having been singled out for a professional foul at a ruck after Robin Copeland had raided forward with turnover ball.
Cardiff were almost in for a try of their own past the midpoint of the half. Dan Fish, who showed some nice touches from full-back, raced onto a long kick but was unable to hold onto the ball with Munster scrambling back.
Munster then had to rearrange their back row as the injured Sean Dougall made way for Paddy Butler, who took up his position at the base of the scrum.
By the half hour mark, the returning O'Gara had tagged on three more points from a close range penalty.
Wexford man Copeland continued to carry well for the Blues, with one particular highlight seeing him gather a high ball and beat Duncan Williams' first-up tackle to give his side some momentum.
With the rain coming down and both defences well manned, there were no further scores - although the Munster pack won a satisfying scrum penalty (Archer winning the plaudits) and Felix Jones saw more of the ball in attack.
But the Blues were back level within six minutes of the restart. Hewitt's angled run saw him evade the grasp of Keatley as he raced over to the right of the posts.
Tovey's replacement Ceri Sweeney converted for a 10-10 scoreline, and increased pressure at the breakdown from the hosts saw Munster pinned back in their half for a spell.
Jones lacked support as he was brought down outside the 22 and Campese Ma'afu stayed on his feet to win a penalty which Sweeney stuck through the posts.
However, a cracking second try from O'Donnell put Munster back in front. The big Tipperary man shrugged off the initial challenges of Copeland and Ma'afu before showing great pace to reach the line ahead of two covering Blues.
O'Gara's conversion made it a four-point game, only for the Blues to respond within minutes. Lou Reed blocked Peter Stringer's attempted box kick, allowing Blues scrum half Jones to touch down the loose ball.
Sweeney's missed conversion left the tie tantalisingly poised at 18-17 in the Welsh region's favour with just over a quarter of an hour remaining.
Munster looked unable to get out of their half as they put the ball through the hands against Cardiff's well-marshalled defence. But with time ticking away, two penalties in quick succession saw them claw back a large chunk of territory.
From the resulting lineout, they used quick ball to send Laulala crashing through in midfield and the late try was enough to seal their third victory on the trot.
|Cardiff Blues Score Card|
|Munster Rugby Score Card|