The Kiwis were strolling to victory after scoring at a point a minute throughout the first quarter and they led 36-4 until collapsing in dramatic fashion to concede four tries in 13 minutes.
The holders’ embarrassment was complete when Sonny Bill Williams, back in the side after a five-year absence, broke clear 12 minutes from the end but lost his footing on the greasy surface and failed to touch down before sliding over the dead-ball area.
Williams’s misfortune was lapped up by the sell-out crowd of 13,965 at the Halliwell Jones Stadium who took the Samoans to their heart.
Williams created the opening for the first try, putting Dean Whare into a gap and Justin Hoffman was in support to finish off for the first of New Zealand’s eight tries.
The Kiwis’ 20-year-old Samoa-born debutant winger Roger Tuivasa-Sheck then demonstrated his class by scorching down the wing to get Simon Mannering over for the first of his two tries before taking Whare’s pass to produce a superb finish himself at the corner.
Shaun Johnson put Mannering in for his second try with a delightful inside pass and his third goal made it 22-0 after 21 minutes.
The Samoans eventually stemmed the black tide and generated the biggest cheer of the first half two minutes before half-time when half-back Ben Roberts produced a fend and a dummy to score his side’s only try.
Vatuvei went over for two tries within nine minutes of the re-start and Johnson fashioned one for hooker Issac Luke as New Zealand stretched their lead to 36-4.
But Samoa hit back with tries from Joseph Leilua, Penani Manumeasili, Suaiia Matagi and Antonio Winterstein to cut the gap to 12 points.
Williams fluffed his chance to making a tryscoring comeback but the Kiwis had the final say when Vatuvei completed his hat-trick eight minutes from the end and Johnson kicked his fifth goal from eight attempts.