''It should be a pretty simple game, so I try to keep it as simple as you can, and it should be easier,'' he said.
Here's the other thing about de Grandhomme: If you're waiting for a blow by blow account of the technical aspects of his innings, you'll be out of luck too.
In a sense that fits with an attitude that while milestones are all well and good, he doesn't toss and turn at night about them.
There was no anxiety as he rapidly sped towards 100; just keep trucking on as he had been. Stopping briefly at 95? No problem.
''Just keep doing what I'd been doing. Five runs, I know it's a milestone but for me (it was) just keep batting and if it's there to go you have to put it away.
''Ninety to 100, it's not a big difference for me.
''If I get a good ball and get out on 99 instead of 100 it's not a big issue for me.''
Had he ever struck it as consistently cleanly before?
''Today felt pretty good. The sticks (bats) I've got at the moment are pretty good so I feel confident with them.''
He's got two new ones. Today was the first outing for one so ''he (the stick) might get a rest''.
De Grandhomme praised the debut innings of wicketkeeper Tom Blundell, with whom he shared a 148-run stand.
''He was very calm, confident and chilled. He made it a lot easier for me too.''
Asked if he remembered breaking a window at the Cricket Museum at deep midwicket in the 2011 season with another thunderous blow, he chuckled: ''Maybe''.
He remembered ''the bowlers let me down'' in February 2013 in a Plunket Shield match at the Basin, left stranded on 99.
There was to be no being left short today. He raised his arms, waved his bat around and, despite the laidback attitude you can be very sure de Grandhomme is, quietly, hugely chuffed.
Fastest test centuries
1. Brendon McCullum - 54 balls
2. Viv Richards - 56 balls
3. Misbah-ul-Haq - 56 balls
4. Adam Gilchrist - 57 balls
5. Jack Gregory - 67 balls
6. Shivnarine Chanderpaul - 69 balls
7. David Warner - 69 balls
8. Chris Gayle - 70 balls
9. Colin de Grandhomme - 71 balls