Ben Foden and James Fish both bagged two tries as Saints kept their Anglo-Welsh Cup hopes alive with a crushing 50-10 success against Scarlets.
Jim Mallinder's men scored eight tries, and it could have been even more in a comprehensive victory under the Friday night lights at Franklin's Gardens.
Foden, who started the game on the wing, and young replacement hooker Fish were joined on the scoresheet by Jamie Gibson, Michael Paterson, Harry Mallinder and Ken Pisi.
It was all too easy in the end for Saints, who are now top of Pool 1 and will progress to the semi-finals if Saracens fail to win at home to Leicester Tigers on Sunday.
Scarlets had started the game at the Gardens well and were 3-0 and 10-5 up in the opening stages.
Billy McBryde's penalty gave the men in red the lead, but Saints were quick to respond, with skipper Foden flying over in the corner for his 50th try for the club.
Myler missed the quickly taken conversion and Scarlets were soon at the Saints door, eclipsing Foden's effort with a try of their own.
Wing Tom Williams was the man diving over after a weaving run that took him past several despairing Saints defenders.
McBryde added the extras to give the away side a 10-5 lead, but again Saints responded quickly with flanker Gibson showing great poise to grab his team's second try.
Myler added the conversion with aplomb, but Scarlets continued to trouble the line, breaking through on a couple of occasions before being stopped by the last man.
Saints managed to hold out though and it wasn't long before they had their third score, with a stylish effort that saw Myler land a crossfield kick into the arms of Foden, who scored.
Myler converted again and Mallinder's men were already seeking the bonus point with 12 minutes to go before the break.
And they were to get the fourth try they wanted as lock Paterson made the most of a lineout drive to dot down.
Myler missed the conversion but Saints boasted a 24-10 lead at half-time, and they soon extended it in the second period as centre Mallinder went over with ease.
Myler added the extras and it looked likely to be a very long second half for Scarlets.
Pisi was the next to score as the Scarlets defence proved porous to a backs move again and Myler made it 38-10 with the conversion.
It was all proving so easy for Saints and after they set up another lineout drive, 20-year-old hooker Fish, on for Mike Haywood, reeled in his first Northampton try.
Myler missed the conversion, but there were still 23 minutes of misery for Scarlets to suffer.
However, with both sides ringing the changes, the game lost its flow and as the rain came down, it was petering out.
But there was still time for Fish to score his second try of the night, with Myler making it a round 50 points with the successful conversion.
Saints: Tuala; K Pisi, Tuitavake, Mallinder (Hutchinson 57), Foden (c); Myler, Groom (Dickson 57); E Waller (A Waller 60), Haywood (Fish 50), Brookes (Hill 50); Paterson, Day (Craig 60); Gibson, Ludlam, Dickinson (Ribbans 57).
Scarlets: D Jones; Williams (A Evans 66), Smith, R Jones, Griffiths; McBryde, Lloyd; Robinson (Myhill 45), Hughes (Fawcett 61), Sebastian (Watkins 72); Helps, Bernardo; Phillips, S Evans (Condy 50), Allen (c).
Referee: Craig Maxwell-Keys