The win sees the Scarlets - last year's beaten finalists - progress to the quarter-finals of the tournament where they will play Neath.
The scores were locked at 10-10 at halftime, but two second-half tries to hooker Marcus Thomas and one to big American backrower David Hodges gave the Welsh champions an unbeatable 30-10 lead.
Home winger Lenny Woodard scored late and set up another try for replacement James Rowles that made the scoreline respectable.
Llanelli were always favourite to go through to the quarter-finals to face Neath at Stradey Park, but Pooler can look back at this match
with pride, Byron Hayward looked lively throughout, and it was his break that lead to the first try from centre Jonathon Hawker.
At that stage it looked like Pontypool fancied themselves for a cup upset, but the Llanelli pack were too well organised, and the backline too sharp to allow themselves to lose this entertaining battle.
Elsewhere, replacement flanker Paul Williams was the hero as Ebbw Vale scraped through to the Principality Cup quarter-finals with an extra-time 13-8 win over a brave Carmarthen Quins at Carmarthen Park.
The Steelmen were lucky to even be in extra-time, with scrum-half Bryan Shelbourne saving his side's blushes with an injury-time penalty goal to level the scores at 8-all. Williams scored the vital try to continue Ebbw Vale's great run in this competition - they've
made the semi-finals in the past three seasons.
Quins fullback Barry Thomas' 68th minute penalty goal gave the home side a shock 8-5 lead before Shelbourne silenced the crowd in the 82nd minute.
Pontypridd fullback Brett Davey bagged 19 points as the Sardis Road men ran over a brave Cross Keys in the second half at Pandy Park to win 49-16.
Bonymaen stunned Cardiff to lead 13-9 at halftime at Parc Mawr before the capital side's class shone through and they ran away with a 41-16 win thanks to the goal-kicking boot of promising young fly-half Nicky Robinson.
Bedwas were brave at the Bridge Field, but Newport's international-laden side was never going to come second in this match. The Black and Ambers led 22-0 at the break thanks to tries to Jason Jones-Hughes and Matt Mostyn, as well as a penalty try.
The home side won the second half 10-5 but were never in contention.
At the Welfare Ground, Bridgend goal-kicker Craig Warlow slotted 19 points - including five penalty goals - to keep the Ravens clear of Newbridge, eventually winning 39-8.
At the Memorial Ground, Neath pounded Glamorgan Wanderers 76-12, with Wales reject Shane Williams running in for four tries.
The All Blacks led 38-0 at the break and eventually scored 12 tries, with fly-half Shaun Connor adding eight conversions.
On Friday night, Swansea thumped Caerphilly 46-21 at Virginia Park.
Principality Cup Round Seven
Bedwas 10 Newport27
Carmarthen Ebbw Vale
Cross Keys16 Pontypridd49
Glamorgan Wdrs12 Neath76
Pontypool 22 Llanelli 30