With Mitchell Santner for company they put on 76 to shift the balance New Zealand's way, and they accelerated the scoring rate as the shadows lengthened across the ground.
The ball boomed over the fence four times from de Grandhomme, and Santner joined in with one of his own over the sightscreen from hapless offspinner Roston Chase.
But then there was a late bounce back from big Shannon Gabriel.
He had been ordinary for much of the day, then bowled both Santner and de Grandhomme to give the visitors a handy fillip.
"I think it's evenly balanced," opener Jeet Raval said tonight.
"We had a good start to the day and they came back later so a tale of two halves. We'll take where we are at the moment."
Truth be told, the West Indies quicks were ordinary in the first session, having been handed the chance to crack into the New Zealand batting order with a bit of nip in the pitch.
Instead they dropped their script, only to pick it up again later in the afternoon.
Just as well because at 154 for one, and with captain Kane Williamson and Raval set, things had the potential to get well out of hand for the West Indies.
Then they grabbed four for 35 in the space of 12.1 overs. When they look back on those wickets some of the New Zealand batsmen will figure they gave the bowlers' a helping hand.
A leg side strangle is never fun for a batsman, as Williamson will testify. But Ross Taylor flashed hard at a ball and edged it to the wicketkeeper; Raval, who impressed in moving his test average to a healthy 47.61 in his ninth match, was beaten by a ball which angled across him; and Henry Nicholls went lbw.
Cue Santner and the Big Man. Raval made a revealing observation that the first part of de Grandhomme's innings, scoring a single off his first 16 balls, particularly caught his eye.
Once in, away he went, booming shots around the park and threatening to undo some decent West Indies work in the middle session and early in the final period.
The Windies got in a jam. They were behind on the over rate so had to bowl Chase. De Grandhomme, well set by then, let rip. It was a perfect storm of sorts and two of his overs went for 17 and 19.
Gabriel had the final say with those late strikes to finish with three for 79 while Miguel Cummins was good value with two for 37 off 17 overs.
"I think if we told ourselves we'd have them seven down we'd have taken that," Gabriel said tonight.
"I think they scored 30 or 40 runs too much, but it was a good day of test cricket."
Fair enough, and much riding on the first session tomorrow.
For the full scorecard, wagon wheel and Manhattan/Worm click here
