James Neesham floored Sri Lanka with bat and ball on his ODI comeback and Martin Guptill scored 138 as New Zealand won the first ODI in Tauranga by 45 runs despite the best efforts of Kusal Perera.
Neesham cracked five sixes in Thisara Perera's 49th over en route to an unbeaten 47 from 13 balls as the hosts blazed 49 runs from the final two overs to post 371-7.
The 28-year-old, playing his first ODI since June 2017, then picked up three wickets as Sri Lanka, led by Kusal Perera (102 off 86) threatened to complete the second-highest run chase in ODIs, behind only the 438-9 South Africa carded against Australia in a Johannesburg run-fest in 2006.
Neesham removed Sri Lanka openers Niroshan Dickwella (76) and Danushka Gunathilaka (43) after the pair had put on 119 for the first wicket inside 18 overs before later dismissing Dinesh Chandimal (10).
Perera became the second man in the match to hit a century to keep Sri Lanka in the hunt for a stunning victory, but the tourists were bowled out for 326.
Lasith Malinga's men had dragged New Zealand back once Guptill - who scored his 14th ODI ton and put on 163 with skipper Kane Williamson (76) for the second wicket - and Ross Taylor (54) were dismissed, with the Black Caps slipping from 274-2 to 317-6 one ball into the 48th over.
However, Neesham then lit up the penultimate over with four sixes in a row and five in total, one of which sailed onto the Bay Oval roof, before also cracking the final ball of the innings for six when he thumped Nuwan Pradeep over cover for his sixth maximum.
Sri Lanka made an excellent start to the reply, only for Neesham to then continue his great day by having Gunathilika caught down the leg side and then bowling Dickwella off an inside edge in his next over.
New Zealand continued to pick up wickets - except for Perera, who completed a superb fourth ODI century from 82 balls when he creamed Matt Henry through extra-cover for four, one of 14 boundaries he hit.
But Perera eventually holed out off Trent Boult in the 46th over, with that wicket proving the death-knell for Sri Lanka's hopes in game one of the three-match series.
See if Neesham, Guptill and Perera impress again at the same venue on Saturday when New Zealand and Sri Lanka contest the second ODI. Live coverage begins at 12.55am on Sky Sports Cricket (channel 404).