If the Stormers were a little more disciplined and a lot more accurate, they could have easily repeated their victory over the Chiefs from earlier in the season.
The home side managed to nullify the Chiefs' dangerous attack and controlled large stretches of the encounter, only to let themselves down through pivotal penalties and untimely handling errors.
Had a couple of key moments played out differently, Rennie's tenure would have come to an uncharacteristic - and controversial - end.
Uncharacteristic, because his attack never really found any fluidity in perfect conditions at Newlands. They only occasionally linked well with the offloads for which these recent Chiefs teams have become known, struggling to regularly break the line and apply consistent pressure.
And controversial, because the second-half sin-binning of Sam Cane was questionable and almost extremely costly. The co-captain's yellow card came after his shoulder made what appeared to be accidental contact with the head of an opponent, wiping away a penalty in a handy position that would have given the Chiefs a seven-point lead with 20 minutes to play.
Upon watching replays, referee Jaco Peyper deemed the incident worthy of a penalty to the hosts and nothing more. But TMO Johan Greeff insisted on further sanction and, after pulling back three points while Cane was off the field, SP Marais soon missed the chance to make the most of the man advantage and put the Stormers in front.
Instead, Cane came back into the fray and Stevenson soon scored the match-winning try, set up by a clever cut-out pass from Cruden, a man approaching the end of his time at the franchise.
"The gift for us is living to fight another day and getting to head home and prepare for a semifinal," the first five said. "It took a massive effort - it takes a lot to come over here and get one over [the Stormers].
"It probably wasn't the prettiest game, compared to what these teams produced earlier in the year. But that's what finals footy sometimes brings. You've got to be able to handle to pressure moments. And we'd much prefer to win ugly than lose pretty."
That maxim will hold true in Christchurch next week, where the Chiefs will be tasked with overcoming both an arduous schedule as they travel back from the Republic and the team who set the pace all season in the Kiwi conference.
"It's certainly a tough test, the way [the Crusaders] have performed this year," Cruden said. "But all we can do is worry about our preparation - we're a confident team, so we believe if we can do the process right the outcome will take care of itself."
Stormers 11 (S. Kolisi try; SP Marais 2 pens)
Chiefs 17 (S. Stevenson try; D. McKenzie 4 pens)
Halftime: 3-9
