Tries from wings Trevor and David James and No 8 Ross Coombs, along with a penalty try, joined forces with two Trevor James conversions to hoist last season's runners up into first place on try count.
Both Bargoed, who beat Mountain Ash 34-14, and Gilfach Goch, who triumphed 33-21 at Rumney, are also on the maximum 10 points after two rounds as they both picked up bonus points on the road.
There were five tries for both teams, with Matthew Llewellyn (2), Nathan Walters, Josh Hughes and Paul Llewellyn crossing for Gilfach Goch, and next weekend's clash between Bargoed and reigning champions Ebbw Vale will be the pick of the season to date.
Tries from No 8 Lewis Wayman, wing Lewis Protheroe, lock Craig Lynch, flanker Adam Coupe and full back Andrew McLaughlin scored Bargoed's tries in their impressive win over newly promoted Mountain Ash, while Ebbw Vale weren't able to pick up a bonus point at home in beating Beaddu 19-9. They still remain unbeaten, however, with nine points from their first two outings.
Blackwood had the boot of outside half Chris Wannell to thank for their 26-19 home win against Tredegar. He kicked four penalties and converted tries from Anthony John and Nathan Gitting to notch 16 points.
A second half try from No 8 Andrew Murphy proved the difference between Merthyr and Treorchy after the two sides had been locked at 13-13 at the break. Murphy's decisive score was converted by Neil Burnett, while the visitors' only second half points came via a Jordan Lloyd penalty.