New Zealand served up a Halloween nightmare for an inexperienced Wallabies side by romping to a record 43-5 victory in the Tri-Nations opener on Saturday and claiming the Bledisloe Cup for the 18th successive year. All Blacks fly-half Richie Mo'unga scored two brilliant individual tries in six first-half minutes and forwards Karl Tu'inukuafe and Dane Coles also crossed as the visitors raced to a 26-0 lead in just half an hour. The pain eased for the crowd of 25,689 at Sydney's Olympic Stadium early in the second half when Australia fly-half Noah Lolesio scored a try on his Test debut but Rieko Ioane and Jordie Barrett blew out the score in the last 10 minutes. Mo'unga converted five of six tries and added a penalty to take his personal match tally to 23 points and ensure the highest victory margin for the All Blacks in 169 Tests against their neighbours. "It's more than relief, it's really exciting and I'm just really proud of the group and excited about what lies ahead," said All Blacks captain Sam Cane. The Tri-Nations, which also involves Argentina, replaced the Rugby Championship after world champions South Africa withdrew from the annual southern hemisphere tournament citing player welfare concerns. The Wallabies had gone into the first Test match on Australian soil this year with hopes high but Dave Rennie's inexperienced side made too many errors and were ruthlessly punished for them. The loss combined with a 16-16 draw and a 27-7 defeat in New Zealand earlier this month handed the All Blacks the Bledisloe Cup with next week's fourth Test in Brisbane to spare. Australia's young side probably needed everything to go right for them to have a chance of beating the clinical All Blacks but they were on the back foot as early as the third minute. Filipo Daugunu was shown a yellow card for upending a jumping Caleb Clarke, although he appeared a little unfortunate having been nudged into his fellow winger's path by Cane.