It was a fifth successive win for the All Blacks, including a 33-16 victory over the Springboks in the first Test at the same venue last weekend, but this was a tough scrap against a brave Lions outfit.
It was a good tune-up ahead of the second Test in Cape Town on Saturday and ensured New Zealand have won all of their matches against South African provincial sides on the tour.
The Lions raced into a 14-0 lead thanks to tries from scrumhalf Nico Steyn and livewire loose forward Sibabalwe Mahashe, the latter with an intercept score.
But the All Blacks hit back with two tries of their own in a fast start, as scrumhalf Noah Hotham and wing Emoni Narawa narrowed the score to 14-12.
There was a lull in the scoring after that before the final 10 minutes of the half, when Lions wing Kelly Mpweku scored with a superb diving finish in the corner.
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The All Blacks were not done either, as Ethan Blackadder went over to leave the score 21-17 to the home side at halftime.
The Lions came out of the blocks quickly in the second period and added two more tries through wing Erich Cronje, after more good work from Mahashe, and captain Francke Horn, and suddenly the lead had ballooned to 18 points.
But the seesaw contest continued and centre Rieko Ioane cruised through some poor defence to score in the 49th minute. When Ioane intercepted shortly afterwards and crossed for his second of the night, the gap was down to just four points.
The All Blacks led for the first time in the game when Blackadder scored his second as the Lions defence battled to keep up with the expansive play of the New Zealanders.
It was a one-point game at that stage and New Zealand put in a massive effort at the scrum to win a penalty on the Lions’ put-in and seize the initiative in the final 10 minutes, before making sure of the win with a late try from Narawa.