South Africa were 218 for six at tea in reply to New Zealand's first innings 268 on day two of the second Test in Wellington on Friday.
Quinton de Kock was not out 63 with Temba Bavuma on 61 in an unbeaten 124-run partnership.
For New Zealand, Colin de Grandhomme has three for 33 and Tim Southee two for 65.
South Africa was 104-6 at lunch, struggling in its reply to New Zealand's 268. But through de Kock and Bavuma's efforts on a flattening wicket at the Basin Reserve the Proteas were 218-6 at tea, trailing by only 50 runs.
De Kock, the aggressor, reached his eighth half century in tests from 55 balls, in 78 minutes with six fours and two sixes and was 63 not out at lunch.Bavuma, the perfect foil for de Kock, took 88 balls and 132 minutes to reach his fifth half century, which included five boundaries, and was 61.
Playing his first international match on his home ground in Wellington, Patel hoped to continue that ascendancy but, though he caused the batsman a few nervous moments early on, he found de Kock in better form than in Dunedin.
De Kock was able to settle in and regained the confidence and fluency missing in Dunedin. New Zealand failed to apply the pressure necessary to staunch his scoring shots and which led to his downfall earlier in the series,
Instead, the Proteas wicketkeeper was able to score freely, especially with pull shots and drives down the ground, helping tip the balance of the match a little in South Africa's favor.
The first session belonged to New Zealand as it claimed four wickets to reduce South Africa from 24-2 at the resumption to 104-6. Colin de Grandhomme claimed two wickets, Tim Southee and Neil Wagner one each, and first innings century-maker Henry Nicholls took two catches at midwicket as New Zealand appeared to take charge.
But the second session was South Africa's as de Kock and Bavuma added 114 runs in what was the first session of the series to pass without a wicket, after 16 had fallen in the previous four sessions in Wellington.