Pro 12: Cardiff Blues 19-22 Ospreys
Cardiff Blues (10) 19
- Try: Dacey
- Con: Halfpenny
- Pens: Halfpenny 4
Ospreys (15) 22
- Try: Tipuric
- Con: Biggar
- Pens: Biggar 4
- Drop-goal: Biggar
Ospreys kicked off Welsh rugby's Pro12 derbies with victory in an enthralling clash at Cardiff Blues.
Visiting fly-half Dan Biggar's opportunistic drop-goal and two penalties gave the Ospreys an early edge against Leigh Halfpenny's penalty.
Blues hit back with Kristian Dacey's converted try, but two more Biggar penalties kept Ospreys in front.
Justin Tipuric's second-half try proved crucial for the visitors as Halfpenny and Biggar's kicking duel continued.
The first Welsh Pro12 derby of the festive season began against backdrop of continuing rows over the future of Wales' regions.
A resolution to those issues has yet to surface, but at the Arms Park these two regions were at least given the chance to underline their value to Wales' professional tier.
Conditions were at times atrocious with a strong wind against the hosts in the opening period and the visitors in the second.
But with Ospreys playing for the first time on Blues' synthetic surface, they and their Welsh capital city rivals produced an entertaining encounter.
Ospreys and Wales open-side Tipuric's skill and footballing ability were among the highlights, particularly in attack in the opening period.
And with Blues' defence having toughened up since the arrival of coach Dale McIntosh from Pontypridd, the contest proved compelling.
Halfpenny and Biggar's kicking shoot-out began early, the former opening the scoring and the latter sending a 40-metre drop-goal soaring between the uprights with the wind at his back.
Biggar added two more penalties, as Halfpenny missed two chances, before the home side's endeavours were rewarded with a well-taken try by hooker Dacey.
Halfpenny began the move, cutting through to set up the field position from which Dacey defied Biggar and the returning Adam Jones' tackles to score.
Home full-back Halfpenny added the conversion to give his side the lead for the second and last time.
Two more Biggar penalties underlined the hosts' disciplinary problems, and as the game wore on the home side's defence also looked less impressive.
Halfpenny reduced Ospreys' 15-10 half-time lead with an early penalty after the break.
But when Tipuric smartly emerged from a driving maul to dash over and Biggar converted, Steve Tandy's side had a two-score advantage to rely on.
Phil Davies' players responded as best they could, forcing replacement prop Mark Thomas into the sin-bin as Cardiff's scrum got on top.
But two more Halfpenny penalties were all they had to show for a brave fight-back that fell short.
Blues: Leigh Halfpenny; Alex Cuthbert, Richard Smith, Dafydd Hewitt, Harry Robinson; Gareth Davies, Lloyd Williams; Sam Hobbs (capt), Kristian Dacey, Benoit Bourrust, Macauley Cook, Filo Paulo, Andries Pretorius, Robin Copeland, Rory Watts-Jones.
Replacements: Gavin Evans for Hewitt (70), Scott Andrews for Bourrust (70), Josh Navidi for Watts-Jones (56).
Not Used: Rhys Williams, Thomas Davies, James Down, Lewis Jones, Chris Czekaj.
Ospreys: Sam Davies; Hanno Dirksen, Tom Isaacs, Ben John, Aisea Natoga; Dan Biggar, Tom Habberfield; Ryan Bevington, Scott Baldwin, Adam Jones, Alun Wyn Jones (capt), James King, Sam Lewis, Joe Bearman, Justin Tipuric.
Replacements: Ashley Beck for Isaacs (61), Jeff Hassler for Natoga (78), Tito Tebaldi for Haberfield (66), Mark Thomas for Bevington (44), Tyler Ardron for Lewis (71), Morgan Allen for Bearman (61).
Not Used: Dwyer, Suter.
Sin Bin: M Thomas (58).
Referee: Jerome Garces (France)
Assistant Referees: Rhys Thomas, Sean Brickell (both WRU)
Citing Commissioner: John Charles (WRU)
TMO: Gareth Simmonds (WRU)