The Blues had led 13-10 going into the final quarter of a pulsating contest, but tries by Regan King, Matthew Watkins and Dwayne Peel sealed the contest.
In front of their largest crowd of the season the Scarlets made a blistering start with prop Martyn Madden driving over inside the second minute.
The Blues, who went into the game on the back of a four-match winning run, enjoyed plenty of possession, but failed to make it tell against some aggressive defence from the home side. They were made to pay for that by another superb solo score by fit-again Wales wing Mark Jones. The Scarlets flyer rounded opposite number Craig Morgan, chipped over full-back Rhys Williams and then won the race to the touchdown for the try of the game on 20 minutes.
The Blues did respond four minutes before the interval thanks to a penalty from Samoan international Roger Warren, a replacement for the out-of-sorts Nicky Robinson.
Warren cut the lead to four points two minutes after the restart and then after Dafydd Jones was sin-binned for an offence at a ruck the Blues took immediate advantage. A strong line-out drive split the home pack and international flanker Martyn Williams was on hand to twist over. Warren was again on target with the kick and all of a sudden the Blues were in the box seat.
They should have extended their advantage shortly after, but failed to nail a clear overlap and the Scarlets somehow held out.
The Scarlets were then guilty of missing their own gilt-edged opportunity, but made amends when No. 8 Alix Popham sent King racing over in the 64th minute. Bowen’s first successful kick of the evening made it 17-13 to the home side and it got even better for the Stradey faithful with a fourth and bonus point try three minutes later.
A pin-point cross-field kick found the arms of wing Mark Jones once more, he flipped the ball inside to centre Matthew Watkins and he had enough pace the race half the length of the field for the score.Bowen converted, then to add to the Blues’ misery, flanker Williams was sin-binned for obstructing his international team-mate Dwayne Peel. Bowen added a penalty and it was Peel who had the final word by diving in at the corner in injury time.