Scarlets (17) 25
Tries: John, Powell, Cooper
Cons: Bowen (2)
Pens: Bowen (2)
Blues (6) 13
Try: M Jones
Con: L Thomas
Pens: L Thomas (2)
Llanelli Scarlets all-but guaranteed Heineken Cup qualification with a win over bottom Welsh side Cardiff Blues.
First-half tries from Phil John and Andy Powell gave the home side a comfortable lead at Stradey Park.
A Martin Jones score after the break brought the visitors to within a converted try, but Vernon Cooper's late score for the Scarlets sealed the win.
Barring some freak results, the Blues must now finish above the bottom Irish side to get a Heineken Cup play-off.
That would be against the third-ranked Italian team.
The Scarlets need just one point from their last three games to guarantee that they finish above the Blues.
Despite the importance of the game to European and Celtic Cup qualification, there was a definite feeling of 'after the Lord Mayor's show' in the early exchanges, following Wales' Grand Slam win on Saturday.
The Scarlets, playing with a strong wind at their backs, opened the scoring with an early Gareth Bowen penalty, but that was cancelled out by a Lee Thomas kick for the Blues.
The stand-off ended after 28 minutes, Powell breaking in midfield after a set move from a line out.
The number eight passed inside to the supporting John for the prop to crash over underneath the posts.
Thomas pulled back a penalty but the try-scoring chances were going to the home side, Wales squad member Mike Phillips held up over the line after a short-range snipe.
The Scarlets encamped in the visitors' 22 and finally got their reward when Powell picked up from the base of a powerful scrum drive for the second try, Bowen's conversion making it 17-6 at the break.
Another Bowen penalty left the home side cruising, but the Blues fought back and with 20 minutes to go prop Jones was allowed to pick up from a ruck five metres out and cross unopposed for a converted try.
Thomas missed an easy penalty shot which would have increased the pressure, before Scarlets captain Cooper put the result beyond doubt with three minutes to go when he crossed from short range.
Scarlets: B. Davies, G. Evans, Watkins, Finau, Selley, Bowen, Phillips, John, Rees, J. Davies, Cooper, A. Jones, Wyatt, G. Thomas, Powell.
Replacements: G. Quinnell for Wyatt (80). Not Used: Maddocks, Gravelle, Griffiths, McDonald, Daniels, Byrne.
Blues: Macleod, Dewdney, Davies, L. Thomas, Morgan, N. Robinson, Powell, M. Jones, G. Williams, Evans, Quinnell, D. Jones, Molitika, Sowden-Taylor, Schubert.
Replacements: R. Thomas for G. Williams (61), Budgett for D. Jones (40), N. Thomas for Molitika (71). Not Used: Llewellyn, R. Smith, Walne, Vaughton.
Referee: George Clancy (Ireland)