The Bulls ran in two tries to one in a somewhat scrappy encounter marred with penalties and handling errors, but Kalamunda coach Josh Heke said he was happy with the effort his side showed to get the win.
After a scoreless first 15 minutes, Kalamunda earned a penalty directly in front of the posts and Alex Oakley made no mistake to open the scoring.
UWA answered back almost immediately through a penalty from Anthony Hondras to level the scores at 3-3.
Hondras then added another three to his tally with a sweetly struck penalty from beyond 40m.
Kalamunda’s ill-discipline continued to hurt them as they infringed at the breakdown, allowing the young fly half to extend UWA’s lead to six points.
After sustained pressure in the UWA 22, Kalamunda went devastatingly close to scoring the first try of the match, only for Nick Pearson to be held up over the line.
In the resulting scrum Kalamunda swung the ball left before coming back infield to find Beau King, who barged his way over from 5m in the shadows of halftime.
Oakley converted with ease to put the Bulls ahead 10-9 at the break.
UWA threw everything they had at Kalamunda at the end, but the Bulls were deserving four-point victors.