Second-round co-leader Josh Geary has fallen to second heading into the final round of the NZ PGA Championship in Auckland.
The New Zealander Geary shot a respectable 69, but was overshadowed by a stunning, bogey-free 64 from Australian Matthew Millar.
He leads by two shots on 17 under par heading into the final round.
"I just got off to a really good start, a lot of those holes early on I like the look of. Twice now I've been 8-under through four (holes) this week," said Millar after tying the course record.
He had claimed a share of the lead yesterday when he chipped in for an eagle on the 18th hole in Remuera, carding a six under par 66 second round.
Mueck had broken the Remuera course record with an eight under par opening round of 64.
The Australian is three shots behind the lead, tied for third.
Four shots behind the lead is national number one Ryan Fox on 13 under par.
The two-time defending champion Michael Hendry had earlier missed the cut with a 73 and a 72.