Missed tackles were a problem that day and the Chiefs were similarly sloppy while allowing the Waratahs to embark on a game-winning blitz midway through the second spell, grabbing three tries in 10 minutes as they lost concentration and cohesion when playing without the ball.
They needed only look at their opponents for an example in defending with the desperation required, given the Chiefs probably should have been well in control after the first 40 minutes.
Three things conspired to prevent that: a Waratahs side who ceded plenty of territory but scrambled well to survive being stretched to their limits, a couple of untimely errors that allowed the hosts to snag two tries while playing without much ball, and a level of inaccuracy that has come to plague the Chiefs' attack.
While it was less pronounced than it has been in recent weeks, the finishing touch always seemed to be missing when a promising break created space in the open field. Aside from one flowing move down the right that saw the Chiefs' little men link to devastating effect, too often their attacking forays failed to find an end result.
Unable to even puncture the opposition defence when Wycliff Palu was sent to the sin bin - and left watching helplessly as turnovers led to a couple of galling tries - there were no prizes for guessing the message Rennie would deliver during the interval. And that emphasis on ball security was immediately heeded by his men, who racked up double digit phases to spread the Waratahs enough for Nathan Harris to find space on the left sideline.
But a couple of concerns remained for the Chiefs. On the tee, Damian McKenzie was unfortunately picking up where Aaron Cruden left off, the pair combining to miss four kicks. And on defence, they were suddenly found seriously wanting.
In fairness to the home side, the Waratahs began to play the type of attacking rugby of which the Chiefs would have been proud, but the tackle attempts appeared tired and communication seemed a problem.
Fatigue was no excuse, given they had barely come out of their bye, and the imminent international break meant nothing would have been kept in reserve. But the Waratahs were strangely rampant for just about the final half an hour, interrupted only when Cruden's cross kick was spectacularly converted by Toni Pulu to offer a glimpse at what might have been.
The international break will be long but based on tonight's evidence, and with the Crusaders waiting on the other side, the Chiefs will have no shortage of work to occupy the time.
Waratahs 45 (Folau 2, Hooper 2, Kellaway, Dempsey tries; Foley 6 cons, pen)
Chiefs 25 (Tamanivalu, Cruden, Harris, Pulu tries; McKenzie pen, con)
Halftime: 17-13
