Llanharan were soon over taken as Lawrence Reynolds and Will Lewis both crossed over twice for Narbeth. A steely second half saw winger Sion Summers and captain Nathan Huish return the home side into the driving seat and with minutes to go it seemed like a Llanharan win. Yet, in a repeat of the two sides' last fixture, a stoppage time try for the Otters, on this occasion from left wing James Russell, left Narberth celebrating a last-gasp, bonus point victory.
There was similar drama at Beddau, as a missed penalty in the closing minutes handed the visiting Blackwood a 34-32 win. Two tries from centre Rhys Humphries and a fine performance from energetic hooker Josh Clarke led the team to their third league victory on the bounce.
Centre Andrew Collins, hooker Sion Crocker and fly half Simon Evans gave Tata Steel the tries needed to overcome Cardiff Met 27-20 while two penalties from Neil Burnett gave Newbridge the edge at Bargoed as it finished 18-13.
Elsewhere, Ebbw Vale cruised to a 45-20 win at Bridgend Athletic and Glamorgan Wanderers let a first half lead slip to lose out 17-14 at home to Pontypool.