The Scarlets sit in second behind Munster on 15 points after the final pool and as one of the best second placed teams in the competition now take forward their European ambitions in the Amlin.

Munster's 51-36 win at Northampton helped the Welsh side's cause.

A typically vocal and rowdy French crowd welcomed the visitors to the Stade Antoine on a bright crisp French evening in Castres with a 10,000+ crowd and plenty of Scarlets travelling supporters to level the balance.

The visitors were 8-6 ahead at the break thanks to a Rhys Priestland penalty and another superbly taken Heineken Cup try for no 8 Mat Gilbert - his second in two starts in the Heineken Cup.

When full-back Rhys Priestland's kick rebounded off an opponent, the Welsh team also had some good fortune. The ball fell into the arms of centre Jonathan Davies, who set number eight Mat Gilbert on a 40-metre charge to the line.

The hosts went in at half time with two Rory Kockett penalties.

The Scarlets showed all the ambition in the opening 20 minutes with a number of opportunities not coming quite to fruition but attacking the Castres home side with some came out with one thing on their mind - a win to take maintain their European campaign.

The experience and tactical awareness of fly-half Stephen Jones was a key element in the victory for the Scarlets, with their most seasoned European campaigner controlling the game with class in the pivotal role.

The Scarlets, who had a much-changed pack from their last outing, relied on a forwards effort that refused to give into the pressure of a giant French pack with physical presence that earns them their top three place in the French league.

But again the much improved defensive work from the Scarlets players proved decisive in this game and the team rose to the challenge with some huge tackles and strong defensive structures to close the game down at key moments and keep the visitors ahead in the game throughout.

And the Scarlets performance given the squad as a whole was carrying 22 injuries this week, brought them a well-earned second place after some neck and neck matches in Pool Two against the best in Europe.

In the second half, it was flanker Aaron Shingler who scored the second sensational Scarlets try sprinting the length of the field after intercepting a pass intended for Mascoe and outpacing the pursuing Castres backs.

Stephen Jones' penalty cancelled out Yannick Forestier's try and Romain Teulet's conversion.

It was a nerve-jangling second half as the scores from Northampton were field to the coaching set-up on the sidelines but with the players unaware until the dying minutes that their victory would take them through.

Priestland, Wales' first-choice fly-half heading into the Six Nations left the field with a knee injury that will be assessed on his return tomorrow and which forced him off in the 54th minute.

But by that time, the visitors had stolen further ahead in stunning fashion.

But after missing a 45-metre penalty, fly-half Jones sent over his final shot from closer range and the visitors held out for a famous win.

TEAMS

Castres: Teulet; Martial, Bonnefond, Garcia, Andreu; Baikeinuku, Kockott; Taumoepeau, Bonello, Wihongi, Murray, Capo, Bornman, Malonga, Masoe (capt).
Replacements: Evans for Garcia (54), Bernard for Andreu (68), Lacrampe for Kockott (70), Mach for Taumoepeau (48), Forestier for Bonello (48), Coetzee for Wihongi (63), Rolland for Murray (68), Caballero for Malonga (61).

Scarlets: Priestland; North, S Williams, J Davies, L Williams; S Jones, R Williams; John, Owens, P Edwards, Reed, Day, Shingler, Pugh, Gilbert.
Replacements: Iongi for Priestland (54), Maule for L Williams (76), R Jones for R Williams (51), I Thomas for John (58), G Davies for P Edwards (51), Timani for Day (65).

Not Used: Phillips, Myhill.

Att: 15,000

Ref: JP Doyle (RFU).