The Kavaliers are now seven points ahead of the second-placed EP after the round four clash ended in their favour at the Boland Stadium.
Following their convincing 43-27 victory over the Leopards in Brakpan, the Valke are now just one point behind EP in the standings, while the SWD Eagles defeated the Border Bulldogs 50-12 to post their second win of the campaign.
SWD have 11 points, the Leopards stay on six points, while Border suffered their fourth loss in a row and must still open their points tally.
Boland raced into a 19-5 halftime lead and although EP fought bravely in the second half, they could not topple the home team in Wellington.
Left wing Cameron Hufkie scored one of the four Boland tries and also added a conversion, while flyhalf Feghon-Leigh Snyders weighed in with two conversions.
EP dotted down three tries, one each through Abduragheem Ismail (scrumhalf), Jayden Bantom (wing), and Aya Oliphant (replacement fullback).
Meanwhile, the Valke converted a 17-3 halftime lead into a 43-27 triumph in their clash with the Leopards in Brakpan. The East Randers' flyhalf Keagan Fortune converted five of the six tries and also added a penalty goal.
Inside centre Tjaart Benade crossed the line twice for the Leopards and fullback Lionel April kicked two conversions in addition to his five-pointer.
In East London, SWD Eagles overpowered the Border Bulldogs 50-12 in an extraordinary game.
Border came out firing on all cylinders, with the Mkhonto Caku-Caku (hooker) and Sipho Nofemele (wing) scoring a try each for the East London side in the opening half.
However, whatever was said during halftime clearly had the desired effect as the Eagles cut loose with eight tries to post a massive win. Mpho Ntsane (left wing, two tries) and Rosco Syster (right wing, three tries) were the main contributors alongside flyhalf Adriaan van der Bank, who succeeded with four conversions.
In the weekend's fifth round action, log leaders Boland travel to Potchefstroom where they will face the Leopards, EP and Border go to battle in an Eastern Cape derby, while the Valke host SWD in Brakpan.