Tries from Alex Cuthbert and Macauley Cook gave the resurgent Blues their third RaboDirect PRO12 triumph in a row as they edged out Simon Easterby’s side.
Rhys Priestland and Ken Owens clawed a losing bonus point back for the Scarlets which keeps them in a European spot. But Gareth Davies’ boot proved vital, leading the capital region to their first win in eight games over the side from the West.
The Scarlets have now lost all four of their Welsh derbies and both teams had a man sent off in what proved to be a feisty domestic battle.
The Blues capitalised on their dominant start to score when Wales wing Cuthbert wriggled over in the corner. Robin Copeland and Cook were repelled before 24 cap winger Cuthbert crashed over the Scarlets line.
Things got worse for the Scarlets when Liam Williams was shown a yellow card for taking out his Wales team-mate and try-scorer Cuthbert. Outside-half Gareth Davies then slotted a penalty to put his team 8-0 up after 10 minutes.
Easterby’s men hit-back through Priestland after half-an-hour. George Earle charged down a Dan Fish mis-kick which Jake Ball pounced upon, he then released the Wales fly-half who finished the try at the posts, but he couldn’t convert his try when it seemed harder to miss.
Referee Ian Davies sent off two players after 55 minutes. Blues No 8 Copeland was shown a red card for stamping on the head of Liam Williams, who was then shown a a second yellow and a red card himself after retaliating with a punch.
Owens sparked the game back into life with a scintillating 50 metre break which ended in his team winning a line-out five metres from the Blues line. They drove over from the resulting set-piece, and it was that man Owens who fittingly touched down to take the Scarlets to within a point.
The Scarlets were close to snatching victory at the death, but the Blues wrestled possession back to secure a win which pushes them above Edinburgh and Connacht into seventh place, just nine points off the Scarlets in sixth.
