He needed just 27 balls for his second 50. It brought back memories of Brendon McCullum's whirlwind at Hagley Oval early last year.
That day, the little skipper in his final test scored so fast in the second half of his innings that no one in the packed sunlit ground picked up how adjacent he was to the world record, until he got to 94.
At that point a buzz reverberated around the ground as people checking their stats information suddenly realised at the same time what was about to happen. Bang, bang and there it was, a technicolour 54 balls, still the world best.
With Blundell, de Grandhomme shared a New Zealand record seventh-wicket stand against the West Indies, 148, and it started to look an unfair fight well before the end, so effectively did they dismantle an already sagging bowling attack.
Blundell, who employs an upright stance with his bat cocked at the crease, grew in confidence, not surprising when the bloke at the other end is fair rattling along, seemingly without a care in the world.
All this late-afternoon fun bumped up New Zealand's run rate and gave the crowd full entertainment.
De Grandhomme acknowledged "we are in a real good positon at moment and with our bowlers, they keep running in over after over".
The pitch is good, he added, which could also be interpreted as it being a help for the West Indies batsmen too.
West Indies seamer Miguel Cummins, the pick of the bunch today on his return to the test side, made it plain what lies ahead.
"The guys are really pumped up about batting again. They know they fell down in the first innings and want to make amends," he said.
There's no getting around the fact they'll need to bat at least two days minimum to have a chance of surviving.
Spare a thought for Ross Taylor, who got to 93 and seemed well set for a record-equalling 17th century – to sit alongside his mentor Martin Crowe and current skipper Kane Williamson – when he fell lbw to Kemar Roach on a referral.
Taylor looked in good touch and having got through a couple of wobbles earlier in the day was two blows away. You sense, though, another chance is not far away, perhaps even at Hamilton next week.
Henry Nicholls had a good day too, after surviving being out caught behind on 24, off a Jason Holder no ball. He'll be kicking himself for not kicking on.
Then again that may have deprived the crowd of de Grandhomme. You can't have everything.
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
For the full scorecard, wagon wheel and Manhattan/Worm click here
