For 92 years, New Zealand had never beaten South Africa in a test series.

But for most that period, they didn’t have a batter like Kane Williamson.

The Black Caps this evening earned a seven-wicket win in the second test and a 2-0 triumph in the series, the historic achievement secured by a cricketer for the ages.

Williamson stroked his 32nd test hundred on the fourth day at Seddon Park, turning what could have been a nervy afternoon into another celebration of a nerveless player.

The 33-year-old made it three centuries in the series, untouchable to the tourists’ understrength attack, and seven in his last seven tests over the space of 12 months.

He pulled into a tie for 11th on the test ton leaderboard, sharing that spot with Australian duo Steve Waugh and Steve Smith. Williamson (172 innings) and Smith (191) will later this month begin a race to No 33 at the Basin Reserve.

That transtasman duel has long loomed as the summer’s highlight — Williamson will earn his 100th cap in the second test at Hagley Oval — with South Africa’s second stringers relegated to an overlooked warm-up act.

Earlier this week, though, the Proteas threatened to crash the main stage, charging through the hosts’ batting order to seize a first-innings lead. But after Will O’Rourke and Glenn Phillips combined in a crucial five-wicket spree on the third afternoon, New Zealand stood 267 runs from history.

The chase seemed challenging; the previous ground record only 210. Offspinner Dane Piedt, coming off five wickets in the first innings, removed both openers to further increase the degree of difficulty.

But then Williamson did what Williamson does, notching his fourth unbeaten hundred in the fourth innings of a test victory, finishing 133 not out while driving the winning runs at 6.03pm.

It was hardly an unexpected outcome. Walking to the ground, many fans must have foreseen that familiar image of Williamson, almost unwillingly, removing his helmet and raising his bat to the crowd.

But its predictability — like a much-loved musician closing every show with the same song — detracts nothing from the spectacle.

That is true also when considering the absence of South Africa’s best bowlers. Given the unprecedented form Williamson has found while handling a spate of injuries, even the tourists’ top attack would have struggled for a way through his impeccable defences.

It was an impossible mission on Friday after the Black Caps had started 227 runs away, a number Williamson metronomically reduced. The run rate rarely strayed, internal calculations no doubt producing the winning day-four equation.

There were missteps, but solely from the former skipper’s partners. Resuming on 40-1 following Devon Conway’s last-gasp dismissal, Tom Latham (30) added nine to his overnight score before spooning meekly to short cover, bringing together a potentially key pair.

Williamson and Rachin Ravindra for a spell appeared set to end the series the way it began at Bay Oval, taking their team past 100 the over before lunch.

Aside from coming down the track to launch Piedt for one splendid six, Williamson had eased into his standard mode of patient accumulation, putting on 64 with Ravindra.

There would be no repeat of their match-defining partnership from the first test. Like Latham, Ravindra (20) was visibly annoyed for chipping Piedt to short cover, yet the wicket was an effective confluence of bowling and field placement.

New Zealand needed 150 more when Will Young (60no) came to the crease, eyeing greater opportunities with three of the top six battling through injury or form. The 31-year-old steadily boosted his chances with a seventh test half-century, joining an unbroken 152-run stand.

Williamson took tea on 92, having taken intrigue out of the chase. Once he reached three figures, pushing to deep point and trotting through for a single, the only remaining question was whether he would be there when the target was attained.

As if there were any doubt.