Superior game management from Cardiff Blues ensured that Ulster left the Arms Park empty-handed this afternoon, as the hosts bade their time to deliver two killer blows in the last 10 minutes and put Ulster's top-four Guinness Pro12 place in jeopardy.
The province remain in the final play-off place for the moment on 46 points, but with closest chasers Edinburgh and Munster both grinding out victories today and moving up to 42 points, Ulster will need to knuckle down in their remaining six fixtures to ensure they are still in contention come May.
The Ulstermen led for over half of today's encounter, with a Craig Gilroy try and seven points from Paddy Jackson's boot keeping them ahead until the one-two of tries from Rhys Patchell and Aled Summerhill combined to strip the visitors of even a losing bonus point.
Ruan Pienaar and Nick Williams were two big-name additions to the starting XV as Director of Rugby Les Kiss made five changes to the side that lost out by a solitary point to the Scarlets last weekend at Kingspan Stadium.
The back three of full-back Stuart Olding and wingers Gilroy and Jacob Stockdale went unchanged, while Sam Arnold replaced Darren Cave in midfield alongside Luke Marshall. Jackson again captained the side from out-half, with Pienaar reinstated at scrum-half after starting on the bench last time out.
Up front, the new prop pairing of Callum Black and Bronson Ross lined up either side of hooker John Andrew, with Peter Browne replacing Alan O'Connor alongside Franco van der Merwe in the second row, and a back row of Robbie Diack, Chris Henry and Williams.
It was a drab first half with no real try-scoring opportunities and three successful kicks from five giving Ulster a slender three-point lead at the break.
The Welsh outfit started out well on top, and Ulster were unfortunate to lose Marshall to a shoulder injury only six minutes in, Cave slotting into the gap as Blues scrummed their way to a kickable penalty which Patchell put wide.
Better work from Ulster on the 15-minute mark saw Williams demonstrate some of the marauding form his future employers at the Arms Park can expect to enjoy next season, but when Jackson's 19th-minute penalty veered even wider than Patchell's earlier effort, the under-capacity crowd were left wondering if the scoreboard would ever spark into life.
The answer came - eventually - on the half-hour when fantastic reach on a penalty to touch from Jackson got Ulster good possession in the opposing '22', and as Blues infringed again right in front of the posts, the out-half slotted over without fuss.
More fine positional kicking - this time from Pienaar - kept Blues under pressure as half-time approached, and with Manoa Vosawai penalised for holding on too long in the tackle inside his own '22', Jackson gratefully gobbled up three more points.
There was still time in the half, however, for Patchell to get his side onto the scoresheet with a penalty as the clock lapsed into the red.
Half-Time Score Cardiff Blues 3 Ulster 6
An Ulster offside early into the second period allowed Patchell to square things up from distance, but a smart interception from van der Merwe as Cardiff threatened from the restart set Ulster on their way, with Arnold showing pace and strength to barge his way through scrum-half Tomos Williams into the '22', where his well-timed pass picked out Gilroy for his sixth Pro12 try of the season.
Jackson converted, but as Blues put together a spirited riposte Ulster had Olding to thank on the hour mark as he put in a try-saving tackle on his opposite number Mark Fish, dragging the full-back into touch a metre from the line when he looked odds-on to ground in the corner.
A poor pass from Williams in defence - straight into the hands of his namesake Tomos - put Ulster back under the cosh two minutes later, but the visitors resisted well enough for a good five minutes to convince Patchell to settle for the three points when referee John Lacey whistled in front of the posts.
Jackson had the opportunity to re-establish the seven-point lead within moments, but inexplicably screwed his kick just the wrong side of the left upright - as did Patchell from just short of half-way with 10 minutes to go.
An apparent hamstring tear put an end to the impressive Arnold's day at this stage, before sloppy defence in the form of a series of missed tackles on Rey Lee-Lo then Patchell on the Ulster left wing saw the out-half get in on 73 minutes for the killer try, which he converted to extend the lead to three.
As Ulster's world fell apart Aled Summerhill dove over in the corner from Ellis Jenkins' pass, Patchell adding the extras to ensure that Ulster left the Welsh capital with nothing to show for their efforts.
Full-Time Score Cardiff Blues 23 Ulster 13
Cardiff Blues (15 - 9) Dan Fish; Blaine Scully, Aled Summerhill, Rey Lee-Lo, Tom James; Rhys Patchell, Tomos Williams
(1 - 8) Brad Thyer, Matthew Rees (c), Salesi Ma'afu, Jarrad Hoeata, James Down, Josh Turnbull, Ellis Jenkins, Manoa Vosawai
Replacements (16 - 23) Kristian Dacey, Thomas Davies, Taufa'ao Filise, Macauley Cook, Josh Navidi, Lewis Jones, Jarrod Evans, Garyn Smith
Ulster (15 - 9) Stuart Olding; Craig Gilroy, Luke Marshall, Sam Arnold, Jacob Stockdale; Paddy Jackson (c), Ruan Pienaar
(1 - 8) Callum Black, John Andrews, Bronson Ross; Peter Browne, Franco van der Merwe; Robbie Diack, Chris Henry, Nick Williams
Replacements (16 - 23) Jonny Murphy, Kyle McCall, Ricky Lutton, Roger Wilson, Sean Reidy, Paul Marshall, Darren Cave, Rory Scholes