The pair took turns being particularly savage on young Josh Finnie, taking 16 off his first over to boost the run rate to close to six runs an over after 20 overs.
The 50-run partnership was brought up in the next over off just 56 deliveries, but reached just 61 before Brownlee was adjudged lbw to give Jacob Duffy his second scalp.
Corey Anderson failed to make much of an impression, falling for six to the same bowler to bring the much-hyped Mitchell Santner to the crease.The youngster lived up to his growing reputation in scoring freely to ensure the innings did not stall despite the Volts largely managing to keep Mitchell in check.
The side had reached 158/4 after 30 overs - an ideal place from which to strike secure in the knowledge they had a potent spin bowling trio well versed in restricting chasing sides.
Sensible batting advanced that score to 184/4 five overs later, with Santner making up for a sluggish Mitchell with an enterprising 33 off 34 balls.
The 200 came up off the first ball of the 38th over as the crucial partnership stretched to 62 runs off 73 balls.
That seemed to help Mitchell flick the switch as he crashed a boundary and a six from the bowling of Duffy to bring up his 50 from 70 deliveries.
Santner fell for a run a ball 45 to Nathan McCullum shortly after but with Mitchell now playing well his job had largely been done.Mitchell picked up successive boundaries off Neil Wagner in the next over - the 40th - meaning the Knights were poised at 226/5 with 10 overs remaining.
He then played intelligent cricket to provide the blueprint for how to pace a 50 over innings.
With Tim Seifert joining the party in attacking Wagner before departing for 25, the Knights always looked likely to threaten 300 on a warm afternoon.
They reached that mark but only barely due to Mitchell struggling to get much strike down the stretch.
He finished on an even 100 not out off 98 balls to guide his side to what should prove a very competitive 308/8.
Northern Knights 308/8 (Daryl Mitchell 100no, Dean Brownlee 61, Mitchell Santner 45; Jacob Duffy 4/64)