The match was the 392nd played by the clubs and Newport's 141st win compared to 193 by Cardiff. Wing Craig Richards snapped up his 15th try of the season and Llyr Lane was the surprise choice as goalkicker, emerging with five successful shots.
At the bottom it was Newbridge who took over as they crashed 41-24 at Llandovery, where home fly half Neil Clapham scored a brilliant individual try, and Llanelli's youngsters gained a surprise 22-16 win at Pontypool Park.
Neath retained second place after a powerful display in winning 37-8 atCaerphilly, while Pontypridd again put their cash problems aside as they routed Bridgend by 54-14 at Sardis Road.
Aberavon kept up the chase by recovering from 0-17 down to defeat Bedwas 44-27 and Carmarthen Quins came back from 9-21 to beat off Cross Keys by 37-30, including eight goals by fly half Giles Thomas.
Another comeback story was at St Helen's, where the All Whites led 23-12 at the interval and kept ahead until seven minutes from time when Ebbw Vale struck with two tries, one converted, to win 24-23.