Seventeen points from Steven Shingler ensured Cardiff Blues won a keenly contested Guinness PRO12 derby meeting with Newport Gwent Dragons 27-16 at a sold-out Arms Park.
The outside half scored his side's first try and made another for Josh Navidi, with three conversions and two penalties completing his match tally.
Kristian Dacey scored the other try for Blues with Ashton Hewitt scoring one for Dragons. Angus O'Brien completed their scoring by converting that try and kicking three penalties.
Dragons made a dreadful start, falling behind after only a minute. A poor kick from O'Brien gave Blues a platform in the home 22, from which Shingler brushed aside some weak tackling to score the opening try.
The visitors responded with their first points with a penalty from O'Brien after an under-pressure Cardiff scrum infringed, but Shingler soon nullified this score with a penalty of his own.
After 18 minutes, Blues suffered a blow when centre Rey Lee-Lo was sin-binned for a high tackle on O'Brien before the outside half recovered to kick the resulting penalty.
Within minutes, Dragons also went down to 14 men with lock Rynard Landman yellow-carded for clearing out Alex Cuthbert without the ball.
Shingler kicked the penalty before their opponents scored their first try. A clever kick through from O'Brien was easily collected by Hewitt for the wing to score with O'Brien's conversion bringing the scores level after 25 minutes.
Both players returned from the sin-bin just in time to see Dacey crash over from close range.
Shingler converted before O'Brien added a penalty from the halfway line.
With the last movement of the half, Blues struck a crucial blow when Shingler sailed through a gap in the Dragons defence to send Navidi over. The conversion was successful and Blues led 27-16 at the interval.
Dragons sent on six replacements in an attempt to reverse their fortunes but the third quarter was error-ridden and uneventful with no additions to the scoreboard.
The Dragons' substitutions made no impact as the hosts continued to dominate the second half and they should have extended their lead but Matthew Morgan missed a straightforward penalty attempt.
Morgan was entrusted with the kick as Shingler had taken a heavy blow, which forced him to leave the field after 67 minutes.
Nicky Robinson replaced him but he could not provide the spark needed to reward Blues' second-half superiority by picking up a bonus point.