Penallta beat newly promoted Blaenavon 17-12 in League One East away from home on September 13.
A first-half try by Penallta full-back Rhys Watkins and three penalties from Johnny Davis gave them a 14-3 lead at the break.
Penallta held on against Blaenavon pressure and a succession of penalties to edge the win.
Senghenydd beat Fleur-de-Lys 36-30 while Risca won 33-20 at Nelson.
The next round of games will be played on September 20 with kick-offs at 2.30pm.