Double defending champions New Zealand will head into the 2019 World Cup in Japan as favourites, but Six Nations Grand Slam champions Ireland have proven there are chinks in the All Black armour. Steve Hansen’s team suffered a major bump on their run-in to the World Cup when they went down to a second defeat in three games by a Johnny Sexton-inspired Ireland, whose provincial side Leinster won the European Champions Cup, Munster also making the last four. That followed the Springboks’ 36-34 victory in Wellington in September that ended a 15-match winning streak for the All Blacks, who have dominated world rugby since securing their second World Cup title in England in 2015 after previous success on home turf in 2011. Excluding the 24-21 defeat by the British and Irish Lions in the drawn series in 2017, it was New Zealand’s first defeat at home since 2009. Ireland’s 16-9 victory over the All Blacks in Dublin in November was built on a teak-tough defence organised by former England assistant coach and dual code international Andy Farrell — the father of England fly-half Owen — who will take over the reins from current coach Joe Schmidt post-World Cup. “As of…