Third-placed Aberavon had high hopes of narrowing the gap at the top to one point, but Newport fullback Richard Davies had different ideas, scoring three tries as the Black and Ambers ran out 31-15 winners.
The former Wales Youth international scored in the first and last minutes of the first half before completing a well-taken hat-trick in the second 40.
Aberavon slip down to fourth on the table, behind Carmarthen Quins on points difference after the Quins sneaked past the crumbling Pontypool side 23-19.
Llanelli's brave attempt to climb off the bottom of the table just failed in a 15-try thriller at Pandy Park.
Scarlets fullback Lee Byrne scored three of his team's seven tries, but Cross Keys scored eight to sneak a 52-45 victory. Home fullback Darren Miles scored a try and kicked six conversions to pass the 100-point mark for the season.
Second-placed Neath kept the pressure on Newport with a 25-6 victory over Pontypridd at Sardis Road, with on-loan Ospreys winger Elvis Seveai'li scoring a second-half try.
Lowly Newbridge earned three valuable points with a surprise 28-16 home victory over an unpredictable Swansea, while Bridgend swapped places with Caerphilly in the table when they beat the Cheesemen 22-14.
Llandovery recorded their fifth win of the season when they beat Ebbw Vale 34-14 at Eugene Cross Park, with fly-half Neil Clapham scoring two tries and
Ricky Williams kicking 14 points. Cardiff moved up the table with a thrilling 26-21 victory at Bedwas, with Elgan Jones and Liam Roberts both scoring try doubles as the Black and Blues overcame a 21-11 deficit at halftime.
Results: Bedwas 21 Cardiff 26, Bridgend 22 Caerphilly 14, Cross Keys 52 Llanelli 45, Ebbw Vale 14 Llandovery 34, Newbridge 28 Swansea 16, Newport 31 Aberavon 15, Pontypool 19 Carmarthen Quins 23, Pontypridd 6 Neath 25.