A breakout display from Matt Henry has put the Black Caps in a dominant position in the first test against South Africa, with Henry's sensational 7-23 slaying South Africa for 95 on day one at Hagley Oval.

At stumps, New Zealand were already in the lead at 116-3, with Henry Nicholls – dropped on five and 23 – unbeaten on 37 and nightwatchman Neil Wagner – also dropped - two not out. Despite being troubled, and losing openers Will Young and Tom Latham cheaply, a 75-run stand between Nicholls and Devon Conway (36) showed how runs could be accumulated on a pitch that Henry made to look unplayable.

Playing his 15th test, which have been scattered over seven years and included an eight-month break before today, Henry showed why the New Zealand selectors kept coming back to the well of a seamer with a test bowling average of 46.2.

This time last year, it looked as if Henry's test career was on the ropes. He had played four tests in the previous four years, and his returns – six wickets at 72.5 – were bleak.

But still, even as he was passed in the pecking order by Kyle Jamieson, the Black Caps persisted with Henry in their squads, and after impressing when taking six wickets against England at Edgbaston last June, he was presented with another opportunity to take the new ball at Hagley, with Trent Boult unavailable.

When you play odd games here and there it's not always going to go in your favour, but it's nice to get a bag like that, it felt really good," Henry said.

"When you wake up and see the overheads and day one at Hagley, you've got your fingers crossed for a bowl, so when we won the toss – finally – it was a great chance to have a bowl here.

"A great start to the test match – a great feeling to be able to do that at home, at Hagley in front of family and friends.