Italian side Zebre shocked Cardiff Blues by claiming their first RaboDirect Pro12 victory in 25 attempts, but the match ended in controversy with the visitors appearing to have an extra man on the field for a passage of play in the closing minute.
With replacement prop Luca Redolfini in the sin bin, Dario Chistolini was called back on to complete the front row for a scrum, without anyone making way for him until the vital phase was over.
That said, the visitors, inspired by New Zealand scrum-half Brendon Leonard, were well worth their 30-25 success, crossing for three tries to the Blues' second-minute effort, made by fly-half Rhys Patchell for centre Dafydd Hewitt, Leigh Halfpenny converting.
Halfpenny, returning to action for the first time since his Player of the Series contribution to the British and Irish Lions' triumph in Australia, supplied 20 points with the boot, but it was to no avail.
Zebre, who led mighty Munster at half-time last weekend, gained territory through runs by pacy Kiwi winger Dion Berryman and Leonard, before the pack heaved flanker Mauro Bergamasco across the line. Luciano Orquera converted and then put the visitors ahead with a penalty from wide out.
Halfpenny missed a long-range attempt to equalise, but made amends with an easier chance three minutes later, only for a further Orquera penalty to restore Zebre's advantage before the interval.
The Blues, who had never lost at home to an Italian team, showed more urgency on the resumption, Halfpenny slotting over from 40 yards, only for Orquera, having gone close with another penalty, to drop a goal from in front of the posts. But the home full-back struck a superb penalty from wide out to level the scores once more.
Lions wing Alex Cuthbert, who had a quiet night, hacked a loose ball downfield, but it bounced into touch, and another Blues attack broke down when Halfpenny, of all people, knocked on. He recovered to kick his fourth penalty, but Zebre scrum-half Leonard sent wing David Odiete through for a try which Orquera improved.
Halfpenny cut the deficit to a single point before a scything Patchell break came to nothing and the visitors escaped downfield for Leonard to finish a flowing move. Orquera's conversion extended the gap to two scores.
The Blues threw everything into attack and Halfpenny kicked another penalty, but it was too late to save the game.