Tasman were pushed all the way but eventually emerged 32-24 winners over Otago to seal their place in the ITM Cup play-offs.
The Makos were grateful to scrum-half Jimmy Cowan, who only joined them earlier this month, as he pulled the strings to down the Championship side.
They led 14-10 at the break, with Cowan setting up the first try for Kieron Fonotia with a quick tap penalty before playing a role in David Havili’s effort just before half-time.
Otago stayed in touch thanks to a try from Jayden Spence and the boot of Hayden Parker.
It looked to be going horribly wrong for Tasman at the start of the second half though, as they conceded two tries, scored by Hugh Blake and Sam Anderson-Heather.
Parker converted both efforts to give the visitors a 24-14 lead but Marty Banks quickly cut the lead back to seven with a penalty just before the hour.
Cowan then grabbed the score that levelled matters, taking advantage of good work from his forwards to cross, with Banks’ conversion making it 24-apiece with 15 minutes remaining.
And ten minutes from time the Makos scored what would be the winning try, replacement prop Ross Geldenhuys the man to get it, sealing a bonus point in the process.
Banks missed the conversion, but slotted a late penalty to ensure there would be no comeback from the visitors.
The win sends Tasman up to second overall in the ITM Cup, level on points with top side Taranaki.
Tries: Fonotia, Havili, Cowan, Geldenhuys
Conversions: Banks 3
Penalties: Banks 2
Tries: Spence, Blake, Anderson-Heather
Conversions: Parker 3
Tasman: 15 Robbie Malneek, 14 Bryce Heem, 13 Kieron Fonotia, 12 David Havili, 11 James Lowe, 10 Marty Banks, 9 Jimmy Cowan, 8 Vernon Fredericks, 7 Shane Christie, 6 Peter Samu, 5 Joe Wheeler, 4 Alex Ainley, 3 Siua Halanukonuka, 2 Quentin MacDonald, 1 Tim Perry
Replacements: 16 Jesse MacDonald, 17 Ross Geldenhuys, 18 Tevita Cavubati, 19 Tevita Koloamatangi, 20 Billy Guyton, 21
Mike Wells, 22 Mitchell Scott
Otago: 15 Tony Ensor, 14 Marshall Suckling, 13 Michael Collins, 12 Jayden Spence, 11 Fa’asiu Fuatai, 10 Hayden Parker, 9 Nick Ealey, 8 Charlie O’Connell, 7 Hugh Blake, 6 Naulia Dawai, 5 Thomas Franklin, 4 Joe Latta, 3 Donald Brighouse, 2 Liam Coltman, 1 Aki Seiuli
Replacements: 16 Sam Anderson-Heather, 17 Michael Mata’afa, 18 Jackson Hemopo, 19 Josh Dickson, 20 Josh Renton, 21 Peter Breen, 22 Kieran Moffatt
Referee: Kane McBride