"I've always said the most important thing is to race consistently and not make mistakes. We had fantastic qualifying speed today to get two poles and that allows you to keep clear of the dangers racing in the mid-pack.
"I am not getting carried away. We have got to come back tomorrow and qualify well and then plan for a 200km race which is going to be a challenge in these track conditions."
Fellow Kiwis Shane van Gisbergen and Scott McLaughlin had mixed fortunes. Van Gisbergen pushed Coulthard hard to claim second in the opening race, but his car struggled leaving him back in 20th in the second after showing some early speed.
McLaughlin had mechanical issues that forced his retirement from the opening race, but zoomed to the lead over Coulthard after qualifying at the front of the grid in the second race. His team made a hasty engine change between races but an electrical issue forced him into the pits while he was still in the race lead.
The 20-year-old was visibly upset as he sat in the motionless car, eventually rejoining the field without sight of the lead, three laps adrift.
There was further New Zealand celebration with the historic first V8 Supercars victory for Erebus Racing and the Mercedes E63 AMG in the hands of Lee Holdsworth, who beat a fast-finishing Mark Winterbottom in the second race.
The team morphed out of Stone Brothers Racing last year with Ross Stone, who was brought up near Pukekohe, the general manager who guided the development of the Mercedes from scratch.
While still very early in the season, Coulthard is now sandwiched between the Red Bull Racing pair of Craig Lowndes (605) and defending champion Jamie Whincup (528) in the championship after both struggled yesterday.
Van Gisbergen moves to fifth in the series with McLaughlin ninth, despite his troubles.