The nuggety outside back made a telling cameo in the second half.
He looked dangerous when he carried but it was his passing game which proved to be the most valuable.
Impressive young flanker Lucas Casey was the first to benefit.
Nareki — or "Joan and the Ricky" according to the AI-generated captions for the livestream of the game — flicked the ball out to him early in the second stanza and the rangey openside slipped over in the corner.
He created another try out wide to help seal the win when he popped an offload to Mackenzie Palmer, who scampered away to score. Palmer nabbed an intercept try in the first half as well.
Otago coach Tom Donnelly was satisfied with the performance.
"It was a good first hit-out for us," he said.
"We had a lot of guys who had their first chance to wear an Otago jersey.
"It was a really even contest in the first half. We did some really good stuff but there is a lot to work on."
"[Nareki] is quality. Anytime we can get him on the park we are a better team."
Green Island hooker Heath MacEwan and young prop Moana Takataka, who was called in late after Ben Lopas was ruled out, also impressed Donnelly.
The Stags started strongly, though.
A break from former Green Island winger Michael Manson led to an early try for Southland.
Prop Morgan Mitchell crashed over and Byron Smith added the extras.
Otago struck back through Palmer’s intercept.
But the home team was making most of the play and loose forward Blair Ryall collected a nice offload in the midfield and stormed his was to the line.
Otago rallied. Prop George Bower muscled his way over from close range and Sam Gilbert drilled the conversion from out wide to level the score.
But Southland got the ball in the red zone again and pounded away before eventually swinging it wide to English winger Charlie Powell, who finished nicely in the corner.
Stags No 8 Semisi Tupou Ta’eiloa had a strong half and took some tackling whenever he charged forward.
Manson looked dangerous as well.
Both sides made extensive changes for the second half.
Nareki made an immediate impact. He drew a defender and got the ball to Casey, who scampered to the corner.
Then Gilbert scooped up a loose pass and used his pace to run in a fourth try for Otago to give his side their first lead of the game.
The presence of Millar at first five and James Arscott at halfback introduced more structure into the game for Otago.
The Stags lineout did not function as well in the second stanza and Otago got some traction in that phase.
They did try to maul over from a lineout, but Southland repelled the attempt and were able to exit their 22.
That was missed opportunity, but Nareki got a lovely pass to Palmer, who dashed away for another try.
Stags captain Sean Withy stepped his way through heavy traffic to bag a late consolation try for the home team.
NPC preseason
The scores
Otago 33
Mackenzie Palmer 2, George Bower, Lucas Casey, Sam Gilbert tries; Gilbert 2 con, Cameron Millar 2 con.
Southland 24
Morgan Mitchell, Blair Ryall, Charlie Powell, Sean Withy tries; Byron Smith 2 con.
Halftime: 19-14 Southland
