Last season's top scorers failed to breach the Force's defence - relying on five penalties to remain in the game - and lost a battle of wills for the first time in almost a year. It's been much longer since the Chiefs were held without a try in Australia - 2001 and a bygone time in transtasman rugby.
The champs' battling qualities had already been established in their three wins so far this season, each more convincing than the previous, but the Force fought with rugged determination throughout a punishing 80 minutes.
Perhaps it was the Chiefs' backline rotation - a strength which generally plays into their hands - or maybe it was the travel demands of their first game outside of New Zealand. Whatever the reason, the Chiefs looked troubled all evening.
An out-of-sorts attack somehow manufactured a halftime lead, but that relied more on fortune than ability. While a generally stout defence was undone by inefficiency in attack, the Chiefs were equally indebted to a bit of luck.
An early goal-line stand eventually produced points for the Force, with captain Matt Hodgson crossing for the try his side's early dominance deserved.
After emerging from their attacking shells in last week's bonus-point victory over the Stormers, the Chiefs struggled for ball throughout the opening quarter. With the Force scrum controlling the off-colour champs, the presumed outcome of the match became less clear.
Aaron Cruden was keeping his side in the game with a number of important penalties, but the first five's influence was negated by the Chiefs' set piece. While their lineout has remained an area of concern throughout the early season, an unusually unsteady scrum in Perth was of equal concern.
A yellow card for prop Jamie Mackintosh left the Chiefs stumbling towards the break, though their late enterprise allowed Cruden to snatch the lead. And that advantage was boosted by Gareth Anscombe's 50-metre effort following the break, leaving the Force with some work to do.
Hodgson soon got that work under way and, if two potential tries weren't ruled out by the TMO, the Force might have secured a more simple victory. But the Chiefs then showed their aptitude for a close-quarter contest, denying their opponents out wide and near the line while dealing with a dozen phases inside their own 22.
The sides traded late penalties to leave the New Zealand side within two but, with 10 minutes remaining, a sustained Chiefs attack soon broke down through a Tom Marshall knock-on, exemplifying a frustrating night for the champions.
Force 18 (Hodgson 2 tries; Ebersohn 2 pens, con)
Chiefs 15 (Cruden 4 pens, Anscombe pen)
HT: 8-9
