Young winger Lee Williams scored his first two tries for the Scarlets, and Dominic Day and Darren Daniel also touched down, as the Llanelli-based side gained Wales’ final automatic spot in next season’s Heineken Cup with a deserved victory over Cardiff Blues.

The 22-year-old Lee Williams, more noted as a scrum half, displayed his finishing skills out on the left wing as he opened his Magners League try-scoring account in style.

Ending a run of five successive defeats and bouncing back from last Friday’s heavy loss to Leinster, the Scarlets handed the Blues their first home defeat of 2009 with Williams, Dominic Day and Darren Daniel helping themselves to tries.

The result condemns the Newport Gwent Dragons to the lowest-placed league finish of the Welsh regions and a play-off against the third-placed Italian team for the 24th and last Heineken Cup place on offer.

It also frees five of the Scarlets to travel with Wales for their upcoming tour of north America, while the four Dragons players chosen must miss out to help their region. The play-off will take place on May 29.

The Cardiff Blues, without their five remaining Lions and big name New Zealanders Paul Tito and Xavier Rush, nevertheless started strongly.

The hosts showed a willingness to throw the ball about, epitomised by a superb flick by Richie Rees to the looping Chris Czekaj.

But they only had two Ben Blair penalties to show for that early spurt and when the Scarlets began to dictate, raking touchfinders from Daniel Evans and Rhys Priestland penned the Blues deep in their own half.

Their persistence was eventually rewarded with two Priestland penalties, sandwiching a first try for Wales Sevens squad member Williams, who managed to get the ball down before the covering Rees dragged him out of play.

Cardiff’s stand-in skipper Robin Sowden Taylor was yellow carded late in the first half and he was still absent when Williams side-stepped his way through the first line of defence before racing 50 yards and sending lock Dominic Day in at right corner.

The Blues sent on Nicky Robinson to try and turn the tide and they cut the deficit with another Blair penalty.

The Scarlets introduced both of their 2009 Lions, fly-half Stephen Jones and hooker Matthew Rees, as they tried to extend their lead, but it was two of the youngsters who created the killer try.

A thunderous tackle on Ceri Sweeney by centre Jonathan Davies saw the ball spill loose and Williams hared downfield to score under the posts.

And then Darren Daniel clinched a bonus point with a breakaway try in injury-time, the Scarlets’ celebrations could really begin.

After watching his side beat the off-colour Blues, Scarlets boss Nigel Davies said: "The pressure was building on us, there’s no doubt about that and a lot of it was down to ourselves.

"It’s unfortunate this year that we’re congratulating ourselves for just about qualifying for Europe.

"But we showed today – and particularly the youngsters in the squad showed today – the potential within the team and they’ve got to believe now and press forward."