Scarlets made it two wins from two in the LV= Cup with a 25-16 victory over London Irish at the Madejski Stadium.
It all started so well for the hosts as they went ahead after only six minutes, when Chris Malone put the Scarlets defence on the back foot with a neat chip over the top which was collected by Daniel Bowden.
When the centre was hauled down in the visitors' 22, the Exiles produced some excellent passing to send Elvis Sevreali'i through a huge gap for the try which Malone converted.
The Scarlets had their first chance to open their account when the Irish were penalised at a ruck and from near half-way Steven Shingler knocked over the penalty.
The outside half then added another after Martin Roberts was high tackled by Irish number eight Chris Hala'ufia, but Malone responded with one for the Irish.
Ben Morgan was then penalised for diving over the top and once again Shingler kicked the goal.
The Welsh side shaded the first half-hour in terms of possession and territory and deservedly took the lead for the first time when Shingler kicked his fourth penalty, after the Irish were penalised at a scrum in their own 22.
After 34 minutes, Malone edged Irish into a one-point half-time lead with a 30-metre penalty.
When Irish full-back Jamie Lennard was penalised for not releasing early in the second half, it allowed the Scarlets to build up their best period of pressure of the match.
Shingler made a neat break which gave the visitors their momentum and Scott Williams appeared to have crossed the line for a try, only for the TMO to rule it out.
The Scarlets continued to maintain their pressure but Shingler missed his first kick of the day from 35 metres.
Malone extended the Irish lead with another penalty in the 57th minute but that success was immediately offset by the loss of replacement Richard Thorpe to the sin bin for tackling Scarlets full back Daniel Evans in the air.
The loss of Thorpe immediately proved costly as from a scrum 35 metres out from the home line, Ben Morgan and Martin Roberts combined well to send Lee Williams over for the try which Shingler converted and then, with six minutes to go, he added another penalty.
Malone missed a crucial penalty with five minutes to go before Shingler knocked over a superb penalty from inside his own half to seal a notable win.
Their success takes the Welsh side to nine points, but Irish look to be heading for an early exit from the competition, without a point from two outings and games against Gloucester and Northampton to come.
London Irish:15 Jamie Lennard, 14 Marcus Watson, 13 Elvis Seveali'i, 12 Daniel Bowden, 11 Jonathan Joseph, 10 Chris Malone, 9 Darren Allinson, 8 Chris Hala'ufia, 7 Steffon Armitage, 6 Kieran Low, 5 Matt Garvey, 4 Nick Kennedy (c), 3 Faan Rautenbach, 2 David Paice, 1 Dan Murphy.
Replacements: 16 James Buckland, 17 Alex Corbisiero, 18 Paulica Ion, 19 Bob Casey, 20 Richard Thorpe, 21 Topsy Ojo, 22 Marland Yarde, 23 Ryan Lamb.
Scarlets: 15 Daniel Evans, 14 Lee Rees, 13 Nick Reynolds, 12 Scott Williams, 11 Lee Williams, 10 Dan Newton, 9 Martin Roberts, 8 Ben Morgan, 7 Johnathan Edwards, 6 Jonny Fa'amatuainu, 5 Dominic Day, 4 Aaron Shingler, 3 Peter Edwards, 2 Emyr Phillips, 1 Phil John (c).
Replacements: 16 Ken Owens, 17 Rhodri Jones, 18 Simon Gardiner, 19 Damian Welch, 20 Nic Cudd, 21 Gareth Davies, 22 Steven Shingler, 23 Andy Fenby.
Referee: Greg Garner