Eight placed Nelson secured a home win against fourth placed Rumney with a 23-16 win. The hosts ran in three tries to the visitors' one as Rumney fall further behind the leaders.
Ystrad Rhondda enjoyed a bonus point win at Penallta as they triumphed 3-30. Penallta scored their only points in a first half which ended 3-11 but the visitors added three more tries in the second period to move within two points of Heoly Cyw.
A tight game between Treorchy and Ynysybwl saw the visitors edge the home team by just three points as they won 23-26. Their three ties to Treorchy's two helped to move them further from the foot of the table as Ynysybwl lost the chance to close the gap on the leaders.
The game between Merthyr and Rhydyfelin was postponed due to the death of a senior club member.