South Africa 308 and 224 for 6 (Elgar 89, du Plessis 56*) lead New Zealand 341 by 191 runs
Scorecard and ball-by-ball details
Moonda: Elgar has bedded in as senior opener
Firdose Moonda wraps up from Dunedin where rain, reviews, drops and runs highlighted the fourth day as South Africa took lead
Could New Zealand's twin-spin attack prove a masterstroke? It may yet depend on the Dunedin weather, with rain forecast for the final day of this nip-and-tuck Test, but late wickets under leaden skies set up what could be a wonderful final day. South Africa, who could barely push their scoring rate above two-an-over, closed with a lead of 191 and four wickets in hand.
The shape of the day - a grey, chilly day that demanded deep resolve from players and spectators alike - changed deep in the final session. After Jeetan Patel removed Dean Elgar, 11 short of becoming the sixth South Africa batsman to make two hundreds in a Test, he cleaned up his bunny, Quinton de Kock, with a beauty (the tally of four successes in four innings not escaping Patel as he celebrated). Between Patel's brace, Temba Bavuma also departed, the ball rolling back off his defensive shot to dislodge the off bail - success for Mitchell Santner who had been ignored for almost 60 overs.
New Zealand's strong end to the day came after being deprived the services of Trent Boult who did not appear after tea due to a sore hip. The second new ball initially went to the two spinners due to poor light, then the immense Neil Wagner - who has had a vast workload - wound himself up for another burst. Boult won't be able to bowl for the first 90 minutes on the final morning and with a tight turnaround of three days to Wellington his prognosis will be a very significant factor.
By close, when the light finally did close in with eight overs remaining, Faf du Plessis suddenly loomed as a crucial figure, unbeaten on 56 from 155 balls with the bowlers for company to try and push the lead over 250. The success for Patel and Santner will encourage him as Keshav Maharaj, who took five wickets in the first, could be a crucial weapon in defending a target alongside his pace trio.
For most of the day it was about Elgar - given out caught behind 73 but saved by the DRS - as he took his time at the crease in the match to almost 13 hours before skipping down the pitch to Patel and finding deep mid-off. However, New Zealand had their chances to remove him earlier and put the heat on South Africa with more time to play with.
On 35, James Neesham found his outside edge from round the wicket but BJ Watling could not gather the chance low to his left. It was the second time in the match that Watling had given an Elgar a life; in the first innings he was spilled down the leg side on 36. Then, on 48, a drive was drilled through the hands of substitute fielder Colin de Grandhomme at cover as Elgar went to his fifty from 144 balls.
Coupled with poor use of the DRS, missing a chance to review against Duminy when he would have been lbw on 20 but using it when he got an inside edge, and dropping the same batsman on 6, it had been a messy first half of the day for New Zealand. However, as events later showed, South Africa's scoring rate meant they were never out of touch and at risk if wickets fell in a flurry.
South Africa resumed just five ahead and Hashim Amla departed early, flicking Wagner to the leg-side trap at midwicket to continue his poor time in New Zealand. Wagner returned after lunch to pin Duminy for a scratchy 39. At that stage South Africa's lead was only 80. Duminy should have gone early when Boult, in the midst of a luckless opening spell, found the edge but Tom Latham, deputising for Ross Taylor at first slip, missed a regulation chance.
For most of the first two sessions Williamson put the onus on Wagner, Boult (with potentially damaging results) and Patel - the latter bowling a 28-over spell - not using Santner until the 65th over. The left-arm spinner created an opportunity first ball when Elgar flicked firmly into Latham at short leg, but the ball ballooned in front of midwicket. Elgar then played a rare attacking stroke, advancing down the pitch to loft Santner straight, but the ball spinning into him created uncertainty and an outside edge fell just short of slip where Neesham and come up from his stance too quickly.
Du Plessis was in no rush to try and escalate the scoring rate against accurate bowling. Late in the day he moved to his half-century off 142 balls with a hint of more aggression, with a brace of boundaries off Wagner, but it was South Africa who were the relieved players when the day ended. Du Plessis will have walked off knowing that his side have not been allowed to dictate terms in this match. Please, don't rain.