Leigh Halfpenny's reliable boot yet again helped propel Cardiff Blues to victory as they brought an end to a four-match winless streak in the Pro12 with a 21-13 success against Newport Gwent Dragons.
The Dragons, who won the Boxing Day clash between the sides 22-16 and were looking to achieve a rare double over their opponents, found themselves 0-9 down through a Rhys Patchell penalty and two from Halfpenny.
Will Harries' try plus two penalties and a conversion from Jason Tovey appeared to give the momentum to the visitors before three further second-half penalties from Halfpenny and Gareth Davies' drop goal confirmed the Blues win.
Having lost the last two Welsh derbies against Ospreys and then Dragons, the home side went on the attack from the off and took the lead on nine minutes when Patchell slotted over his penalty from just inside the near touch line.
The fly-half had assumed kicking duties with Halfpenny having taken a knock although the full-back had a chance to notch an early kick himself three minutes later after Dragons knocked on, but his long range effort went off target.
It was then Dragons turn to miss the target from the tee as Tovey's 15th minute penalty rebounded off the posts before his second attempt, after the visitors were penalised at the scrum, flew wide.
And they were made to pay for their misses when Halfpenny sent over his side's second penalty from the ten metre line on 22 minutes for a 6-0 lead - Dragons having been pinged for not rolling away.
Despite having not won in the league since round seven, the Blues were showing more adventure going forward with a series of slick hand offs but were unable to get near the try line.
But with the visitors again penalised in the breakdown, Halfpenny was on hand to slot over another penalty to keep the score line ticking over to 9-0 after 28 minutes.
Yet it was the Dragons, in their first meaningful attack of the game, who got the opening try of the game via Harries.
Ashley Smith collected a high kick inside his own half before feeding Lewis Evans on the wing. The back row held off his pass just long enough to evade the challenge of Halfpenny and leave Harries to stroll in, Tovey with the extras for 9-7 on the half hour.
There was further bad news for the Blues with Patchell forced off with a knee injury, Davies on in his place before Tovey's 34th minute penalty then edged the Dragons in front for the first time on 34 minutes.
The Blues enjoyed a period of possession in the closing stages of the first half, before a quick break and dummy from Davies but his off load on the wing failed to find a teammate and the dead ball brought about the half-time whistle.
With the rain coming down during the interval, the second half was going to make for difficult handling so the Dragons fans would have been happy to see Tovey send over his second penalty to extend their lead to 13-9.
He had a chance to increase the difference to seven points but his kick went off target on 49 minutes.
The game continued to be a tight affair and the reliable boot of Halfpenny pulled the Blues to within a point on 54 minutes when his side won a penalty after Toby Faletau was adjudged to have fouled in the air from the line out.
The Dragon's penalty count was proving costly and when they were pinged again, this time for not rolling away, Halfpenny was left the simple task of edging his side back in front 15-13 with a little over 15 minutes to play.
Halfpenny then missed the chance to extend the lead when his penalty flew off target but Davies ensured it would be a five-point game with just under ten minutes left as he sent over a drop goal.
Dragons needed to work the ball into the opposition territory but instead it was the Blues who continued to push and while Halfpenny was off target from 58 metres, he would not miss from in front of the posts on 79 minutes to confirm victory and deny the Dragons a losing bonus point.
For Cardiff Blues:
Pens: Halfpenny 5, Patchell
For Newport Gwent Dragons:
Pens: Tovey 2
Cardiff Blues: 15 Leigh Halfpenny, 14 Alex Cuthbert, 13 Richard Smith, 12 Dafydd Hewitt, 11 Harry Robinson, 10 Rhys Patchell, 9 Lloyd Williams, 8 Robin Copeland, 7 Josh Navidi, 6 Rory Watts-Jones, 5 Filo Paulo, 4 Macauley Cook, 3 Benoit Bourrust, 2 Marc Breeze, 1 Sam Hobbs (captain).
Replacements: 16 Rhys Williams, 17 Gethin Jenkins, 18 Scott Andrews, 19 Chris Dicomidis, 20 Ellis Jenkins, 21 Lewis Jones, 22 Gareth Davies, 23 Gavin Evans.
Newport Gwent Dragons: 15 Daniel Evans, 14 Will Harries, 13 Pat Leach, 12 Ashley Smith, 11 Matthew Pewtner, 10 Jason Tovey, 9 Wayne Evans, 8 Toby Faletau, 7 Lewis Evans, 6 Netani Talei, 5 Rob Sidoli (captain), 4 Matthew Screech, 3 Dan Way, 2 T Rhys Thomas, 1 Owen Evans.
Replacements: 16 Sam Parry, 17 Aaron Coundley, 18 Francisco Chaparro, 19 Adam Jones, 20 Nic Cudd, 21 Richie Rees, 22 Steffan Jones, 23 Ross Wardle.
Referee: Leighton Hodges (Wales)
Assistant Referees: Neil Hennessy, Gwyn Morris (both Wales)
TMO: Paul Adams (Wales)