Blindside flanker Kyle Harris threw himself around the track, in keeping with his impressive tournament, and openside Mitch Jacobson hooked into his work with relish. Sanders too was industrious and set up Jacobson's try with a dash from the base.
Simon Hickey injured his leg in the first half and limped off early in the second, replaced by Damian McKenzie with Richie Mo'unga shifting from fullback to No 10.
The rain ceased and New Zealand started to string some useful movements together. One of those led to the bonus point try and secured the passage to the semifinals.
Second five Kaveinga Finau grubbered through and Mo'unga appeared to knock the ball on, but the TMO ruled that it came off his knee. Scotland made a meal of tidying up and Renton pounced for his double.
New Zealand relaxed after their fourth try and though the changes were wrung, it was like a weight had been lifted from their shoulders. McKenzie embodied that, a shimmy and step off an inside ball from Mo'unga sealing their fifth try. Three more followed.
New Zealand 54 (Josh Renton 2, Tom Sanders, Mitch Jacobson, Damian McKenzie, TJ Faiane, Vince Aso, Leon Fukofuka tries; Richie Mo'unga 5 cons, Simon Hickey 2 cons)
Scotland 7 (Damian Hoyland try; Gavin Lowe con)
HT: 21-0