Wales No.8 Popham crashed over in either half while young outside-half Craig Evans converted one and added two penalties for a vital Celtic League win. The result saw the Scarlets leap-frog local rivals the Ospreys, who beat Munster days earlier, into sixth place and more importantly in the battle for Heineken Cup qualification.
Meanwhile, Munster will be hoping bad luck does not come in three after crashing to a second defeat in Wales in the space of five days ahead of their European final in Cardiff. Munster rested several key players though the Scarlets also handed first regional starts to outside-half Evans and centre Gavin Evans.
Munster led through a Jeremy Manning penalty against the run of play but the Scarlets were finally rewarded for dominating the first half when Popham scored tw minutes before half-time. The Scarlets pack rumbled half- the length of the field to set up a scrum five yards from the try line, Popham touching down after a devastating shove.
Manning and Evans traded penalties at the start of the second half to leave the Scarlets 8-6 ahead until breaking through on 65 minutes. The fresh legs of Aled Gravelle proved deadly when the replacement hooker surged forward from behind a ruck. He was haul down yards from the line but Popham was unstoppable from close range as he picked up and drove over for his second.
The Scarlets had Vernon Cooper sent to the sin bin for stamping yet still managed to extend their lead with a second penalty that put the result beyond doubt.
Scarlets: L Byrne; Garan Evans, R King, Gavin Evans, T Selley; C Evans, C Stuart-Smith (D Peel, H-T); I Thomas, M Rees (A Gravelle, 62), C Dunlea (J Davies, 67), V Cooper (capt), H Louw (A Jones, 62), I Afeaki (J Mills, 52), A Popham, D Jones
Tries - A Popham (2)
Con - C Evans
Pen - C Evans (2)
Munster: D Hurley; A Horgan, T O'Leary (M Mullins, H-T), M Lawlor, I Dowling; J Manning (P Burke, 70), P Stringer (M Pendergast, H-T); E McGovern (T Ryan, 76), P Humphreys, F Pucciariello (D Varley, 47), T Hogan, M O'Driscoll (D O'Callaghan, 65), D Leamy (A Quinlan, H-T), J O'Sullivan, S Keogh (capt)
Pen - J Manning (2)
Referee: M Changleng (Scotland)