De Grandhomme now averages 49.5 in New Zealand, at a strike rate of 83, and today's innings also showcased his sensible side.
After racing through to 50 off 36 balls, South Africa turned to spinner Keshav Maharaj with the light fading and stumps nearing.
Having holed out in the first test to part-time tweaker Aiden Markram, and having a habit of taking on spinners and trying to hit them out of the ground, South Africa were hoping for a rash shot that would cause a killer blow to end day two.
Instead, de Grandhomme defended 16 straight dot balls, ensuring he'd be walking back out to the wicket tomorrow morning alongside Mitchell, who was full of praise for his partner.
"It's good fun to bat with [de Grandhomme], he put a lot of pressure back on their bowlers, which is what he does naturally, and he hits the ball so clean he makes it look so easy at times," said Mitchell.
"It was awesome for him to go out there and play his natural game and keep trying to hit the bad balls and put them away.
"It was a great knock by him, but we also know there's plenty of work to be done. It will be a great challenge."