South Africa captain Faf Du Plessis called on his bowlers to be "relentless" after his century helped put his team in control of the second Test against New Zealand.
A grinding Du Plessis made an unbeaten 112 before declaring at 481-8 on day two at SuperSport Park in Centurion on Sunday.
The reward came before stumps as New Zealand were reduced to 38-3, and the skipper wants more of the same from his bowlers.
"In hindsight it looks like a good toss to have lost," he said.
"It looks like the cracks are going to play a role. If our bowlers can be relentless on hitting that fourth stump back of a length with a few bouncers, it's going to be challenging."
Du Plessis added: "We are expecting it to be tough, we aren't expecting to just come in and get wickets tomorrow.
"We want to work hard for our wickets and if they come our way a little bit easier that will be great.
"We are expecting a grafting day with the ball tomorrow to set it up for the following two days."
Neil Wagner took 5-86 for New Zealand, but the hosts' top order were dominant as JP Duminy (88) and Quinton De Kock (82) joined Du Plessis in contributing well.
Paceman Tim Southee, who finished with 1-114, felt too much went wrong for the tourists.
"I think as a group we felt we passed the bat a fair bit and it was just one of those days," he said.
"The ones that did a little bit almost did too much and then credit to South Africa, especially Faf, who played well and was patient and then put the bad balls away as well.
"It is frustrating when you have days like that when you beat the bat and a guy even on 80 or 90 still plays and misses.
"It was one of those days, one of those Test matches so far where it almost did a little bit too much at times and didn't catch the edge."