"Gregory played really well to fulfil the role of anchoring the top to ... allow our exciting middle order to set off," he said after No 5 Tom Bruce racked up a quick-fire 78 from 74 balls.
Volts century-making openers Hamish Rutherford and Brad Wilson are 71 and 44 not out, respectively.
Malan was mindful NZC wanted every venue in the country to work on exposing its character on wickets.
"It's a work in progress with the groundsman at Saxton Oval because they are still trying to find what that character is," he said, not expecting it to break much although it was offering some slow turn to the tweakers.
"It's raining tonight so, hopefully, it'll stop."
The wicket had a different bounce on day three with some deliveries staying low while others "spat up" but the other variable for both sides to factor in was their field settings.
He was hopeful Otago were of the same mindset should play resume "and give us a whack at it" within the ambit of runs required from a competitive number of overs.
"What score they'll be comfortable with I don;t know but we've thrown the ball in their court," he said of the William Young-skippered Stags.
