New Zealand stretched their lead to 376 runs as they maintained their throttle-hold on understrength South Africa during day three of the first Test on Tuesday.The visitors were skittled for 162 at Mount Maunganui in response to New Zealand’s 511, before being sent back into the field after the follow-on wasn’t enforced.The Black Caps were 27-1 at tea and on course for an emphatic win over their inexperienced opponents with seven sessions to play on a deteriorating Bay Oval pitch.Tom Latham was trapped leg before wicket by Dane Paterson, leaving fellow-opener Devon Conway and Kane Williamson both at the crease on nine.The depleted nature of South Africa’s side continued to be exposed by the hosts, who captured the last six wickets for 82 runs on Tuesday.The top score was 45 from Keegan Petersen who, with 12 caps, is the most experienced batsman in the tour squad after most of their first-choice Test players remained behind to compete in the domestic Twenty20 competition.Petersen lost his overnight partner David Bedingham for 32 when trying to hook seamer Matt Henry, before Ruan de Swardt followed for a second-ball duck in the same over.Wicketkeeper Clyde Fortuin, one of six Proteas debutants, departed for nine just before the tourists went to lunch at 129-7.The tail was wrapped up quickly, with Henry taking 3-31 and Mitchell Santner capitalising on spin-friendly conditions to finish with 3-34.Rachin Ravindra, who scored a career-high 240 for New Zealand, continued a fine match by claiming two wickets, including that of Petersen with a mis-timed drive.