First half tries from Craig Atwell and Dom Franchi had given Newport plenty of confidence and although the Quins fought back, the boot of Geraint O'Driscoll guided the visitors home.
In the other games to take place last Friday, Bridgend secured a vital home win over Neath as they edged their regional rivals 23-17 at The Brewery Field. Fly half James Dixon did the damage, booting six penalties and a drop goal in a controlled kicking display. Ashley James scored the only try for the Ravens with flanker Graham Knoop producing a superb individual display.
He said: "It was fantastic to play 80 minutes in a Ravens jersey and come out with the win. It's great to hear how passionate the Bridgend supporters are from the side - they are often just as fired up as the Ravens players.
"Weeks and months of training really showed on Friday and I thought the pack's performance was immense, especially come set piece time. A lot of credit must go to the coaching staff who have continued to take a positive approach to the team's recent performances and who continually back and support the team in all circumstances."
At Pandy Park, Cross Keys proved far too much for visitors Cardiff as Greg Woods' side powered away in the second half. Keys eventually ran out 45-13 winners with Daniel Hodge scoring a brace of tries. Nathan Trowbridge and Jevon Groves completed the scoring with fly half Dorian Jones converting all four tries and kicking four penalties.
On Thursday evening, Aberavon claimed a vital 22-11 victory over Llanelli at the Talbot Athletic Ground while the next day, Bedwas shocked Llandovery at Church Bank. The visitors defied two yellow cards - forwards James Thomas and Aaron Coundley were yellow carded - to claim victory as four penalties from fly half Richard Powell proved key. And when Rory Budina flew over just after the hour, Bedwas had done enough to return home with a win.
With Carmarthen Quins slipping up, Pontypridd knew they could take advantage if they were to beat Swansea on Saturday morning. However, things did not go to plan initially as the All Whites built up a 16-5 interval advantage.
Wales Under 20 centre Garyn Smith had scored early on for Pontypridd but Swansea were the dominant force and with 40 minutes gone, an upset looked on the cards. But in the second half, Pontypridd woke up and a double from full back Geraint Walsh, either side of a Thomas Hetherington score, took the visitors to a 22-38 win. Fly half Dai Flanagan added two conversions and a penalty.
Principality Premiership results:
Aberavon 22-11 Llanelli
Bridgend 23-17 Neath
Carmarthen Quins 21-25 Newport
Cross Keys 45-13 Cardiff
Llandovery 12-17 Bedwas
Swansea 22-38 Pontypridd