He was downplaying his calibre yesterday, suggesting he was just being given a chance.
"I don't think I have moved ahead of Millsy [Muliaina]," he said. "I have a lot of respect for the guy, I have just been given this opportunity to go out there and put the jersey on. I want to put everything out on the paddock and repay the faith the selectors have given me."
Dagg thought his season was done after tearing his thigh muscle from the bone during the Super 15 series.
An MRI and x-rays did not give him much hope either.
But he returned and one test at Port Elizabeth convinced the selectors Dagg was World Cup ready.
"I guess it was just one flukey performance and I just have to keep getting out there every day and train hard and keep working on it," he said.
"Next game I could have a shocker and then everyone will go 'that is only one game where you played well' so I will do my best and get out there and hopefully this game I can do well."
Starting the first World Cup game in his own country was massive, he said, and his parents would be at Eden Park to share the experience.