Toomey, who only turned professional last month, after a stellar amateur career, when he represented his country, played The Hills with the temperament of a veteran.
The Waikato man scored a solid 6-under 66 on The Hills in outstanding conditions.
''I think it is a special place as it is Queenstown on its own and then to be playing in the Open, and open up with a number like that it is very rewarding,'' Toomey (24) said.
''It is one of the most rewarding rounds I have ever played, to be honest. From tee to green was basically flawless. Even today there was some missed opportunities and I got some bonus putts as well.''
He will play today at Millbrook, a course familiar to him.
''It has a bit of a different set-up to The Hills ... game-plan wise it will be a little different. But on the whole, mental [approach] is the most important thing.''
His expectations this week are high - he wants to win the tournament.
''My whole life was being about making that transition and going forward from that. So there is nothing too different. You could not get the smile off my face on the first tee.''
The adrenaline was pumping at the first tee but he soon calmed down and just treated the game as he had since he first played when he was 6.
Fellow Kiwi Ryan Fox said he felt his round yesterday was really solid.
''I think I only hit two bad shots all day. I got away with one of them and unfortunately got a bogey with the other one,'' Fox said.
He sits on 4-under 68, and is still handy in a crowded field.
''I hit a lot of nice shots out there [and] left a couple out there but I have always struggled a bit on the greens around The Hills.
''But as the cliche goes, you can't win the tournament in the first round but you can play your way out of it.''
