|European Rugby Champions Cup|
|Northampton (7) 15|
|Tries: Pisi, Waller Pens: Hanrahan Cons: Hanrahan|
|Scarlets (6) 11|
|Tries: Davies Pens: Shingler 2|
Northampton Saints secured a narrow win as Scarlets came away with the losing bonus point in their European Champions Cup opener.
Ken Pisi's try gave Saints an early lead, but Scarlets responded with two Steve Shingler kicks before half-time.
Gareth Davies crossed to give the Welsh side the advantage after the break.
But Alex Waller went over and JJ Hanrahan added a penalty to hand the victory to Northampton - who survived for 20 minutes with 14 men.
And Scarlets will be left to rue four missed kicks at goal which cost them valuable points at Franklin's Gardens.
Saints reached the quarter-finals of the competition last season and finished top of the Premiership table in May - only to be beaten to the title by Saracens.
But they have only won once in three games this term, while their Welsh opponents have won six from seven in the Pro 12.
The hosts got off to the perfect start when Pisi fended off a late tackle to tap down after only six minutes, and Hanrahan duly converted.
Shingler then got Scarlets off the mark but a turnover from Waller sent Northampton on the charge and Luther Burrell went over at the other end.
However, after deliberation from the television match officials, it was ruled out and George North was shown a yellow card as the Wales international was adjudged to have fouled Michael Tagicakibau in the build up.
Scarlets could not make the extra man count but did land their first try after the break, when Davies sprinted through the Saints defence to cross over.
Northampton regained the lead instantly when Waller touched down from a rolling maul, but found themselves back down to 14 men as Jamie Gibson received a yellow for not rolling away.
Hanrahan went on to slot a penalty to make the game safe but Scarlets were able to come away with a point.
Northampton director of rugby Jim Mallinder: "It was an arm wrestle but it's a cracking start for us.
"It's far too early to be talking about winning the competition as we are in cracking pool.
"We have Glasgow away next, who beat us away last time and they will play like the Scarlets so we need to be strong in the set piece."
Scarlets coach Wayne Pivac told BBC Radio Wales: "The attitude in the side has changed now where we come into these games to win, no matter what team we put out on paper.
"We had opportunities and it was through our errors and game management that we let that one slip."
Northampton: Foden; K. Pisi, G. Pisi, Burrell, North; Hanrahan, L. Dickson; A. Waller, Haywood, Brookes; Craig, C. Day; Gibson, Wood, S. Dickinson.
Replacements: Tuala for K. Pisi (52), Myler for G. Pisi (61), Fotuali'i for L. Dickson (71), E. Waller for A. Waller (63), Hill for Brookes (63), Harrison for Craig (64), Paterson for C. Day (19)
Not Used: Williams
Sin Bin: North (20), Gibson (65)
Scarlets: Thomas, Tagicakibau, Owen, Parkes, van der Merwe, S. Shingler, G. Davies, R. Evans, Phillips, Edwards, Ball, M. Paulino, A. Shingler, J. Davies, Barclay.
Replacements: T. Williams for S. Shingler (73), A. Davies for G. Davies (73), Rawlins for M. Paulino (56), Price for A. Shingler (79).
Not Used: Myhill, John, Taylor, King
Ref: Romain Poite (France)