Kane Williamson hit an unbeaten century as New Zealand chased down a victory target of 267 to beat South Africa by seven wickets on the fourth day of the second test on Friday and clinch a first ever series win over the Proteas. South Africa, severely depleted with most of their top players back home playing the SA20 tournament, battled hard to even up the series at but were unable to make sufficient inroads into the home batting order. Williamson’s patient 133, his 32nd test century, mostly came in a partnership of 152 with Will Young (60 not out) that got the Black Caps over the line in what was a record fourth-innings run chase in a test at Seddon Park. The 2-0 series triumph will come with a hefty asterisk due to the inexperience of the South African squad and Neil Brand’s tourists will take great credit for taking the contest down to the wire after losing the first test by a thumping 281 runs. “It was a pretty old fashioned sort of ding-dong test match,” said New Zealand skipper Tim Southee. “Kane played an absolute blinder, as he has done for so many years, and he was well assisted by Youngy today.” The hosts resumed on Friday on 40-1 with the match very much in the balance after Devon Conway had been dismissed by spinner Dane Piedt in the final over of play on day three. Opener Tom Latham added nine runs to his overnight tally before he departed for 30, caught by Zubayr Hamza off Piedt, but that just brought Williamson to the crease.