He leaped up and applauded generously as you do when someone you have invested in comes through for you.
Guptill went on to post 156 - his third test 100 - on the opening day of the test against Sri Lanka at the University Oval yesterday.
It has put his side in a strong position at 409 for eight and was a welcome return to form.
"Any time you get a hundred, you are pretty satisfied,'' Guptill said.
"But to kick on and get to 150 was also pretty pleasing and just set the game up well for us.''
Guptill survived two lbw appeals on 78 and the second would have been out had Sri Lanka opted for a review.
The touring side waved that option and Guptill marched on.
To have bounced back from a disappointing tour of Australia was a boost, he said.
"[You take] a lot of confidence. I just tried to go out and be as positive as I could be and show good intent. I was able to rotate the strike and get some good partnerships going.''
He did that with Kane Williamson.
The pair put on 173, which was a New Zealand second-wicket record against Sri Lanka.
The 29-year-old right-hander did not feel under any more pressure than normal despite a lean run in the lead-up.
"I did not have a lot to lose so I just tried to be as positive as I could and have some fun.''
The Black Caps were able to bat positively and rattle on quick runs.
But with six wickets falling in the last session, the visiting side managed to claw back some momentum.
"It was not ideal but that is cricket. The second new ball on a fresh wicket is always going to be pretty tough to get through, but we have an opportunity to push towards 450 [this] morning and then have a dip and, hopefully, bowl them out cheaply.''
