It was obvious from the opening minute that the Stormers were seeking revenge from their humbling at the hands of the Chiefs in last year's quarter-final, sparking an all-in dust-up that was indicative of what was to follow.
And, for all their ferociousness and physicality, the home side never let their emotions interfere with what was a cleverly-executed game plan, attacking patiently around the fringes and posing too many questions for a previously impressive Chiefs defence to handle.
It was close to a complete performance, considering the Chiefs also played their part by scoring two tries of the highest quality, and left Rennie with little choice but to tip his cap.
"If we'd played really poorly and lost I'd be disappointed," the coach said. "But I thought the Stormers were excellent and deserved their win.
"When we played them here in [last year's] quarter-final, defensively they really battled with the pace of the game we were playing. But clearly they're much better conditioned and much better organised. Both on attack and defence, they were really strong."
Rennie believed that 60-21 thrashing from nine months previous would have played a big part in the Stormers' preparations and, similarly, expected his side to now react in a manner that can sometimes be manufactured only in defeat.
"They were clearly emotional and hyped up for the game, and so they should have been," he said. "You hate to lose, but you do get a kick in the backside. We'll dust ourselves off and prepare well for the Cheetahs in Bloemfontein."
The Chiefs will be boosted next week by the return of co-captain Sam Cane from concussion and further buoyed by having suffered no new injuries from a bruising encounter.