Tasman will join the big boys in the ITM Cup's Premiership division next season after they beat Hawkes Bay 26-25 in the Championship decider in Nelson tonight.
During the past month, Tasman's ability with the ball in hand took them to the top of the Championship and they enjoyed home advantage for both of their playoff games.
They took Southland apart last week in the semifinals and were ruthless in their execution tonight as their running game laid the platform in the first 40 minutes before they defended stoutly for much of the second half to hold on for the result.
Hawkes Bay, who had to beat Otago in Dunedin last week to earn their spot in the final, came to Nelson with plenty of endeavour and with halfback Alby Mathewson in dangerous form, they looked likely throughout the contest.
Replacement No 9 Chris Eaton scored from a brilliant counter-attacking move in the dying stages which left it to Ihaia West with a sideline conversion to win the game but the youngster couldn't convert.
The first half was a frenetic affair as the game was played at break-neck speed with both sides full of vigour at the breakdown, while Hawkes Bay flew up in defence in an effort to suffocate the Tasman backline.
The visitors scored first when West found a hole and put fullback Zac Guildford in to space and the former All Black did the rest with a five-pointer next to the posts.
Behind on the scoreboard, Tasman roared in to life though as their potent running game began to click with tries to Bryce Heem and the impressive Liam Squire.
At 18-10, Hawkes Bay were still in the hunt and after they earned a penalty on the stroke of halftime it seemed they would go to break down by only five points but West tried to push the tempo and took a quick tap from close-range and threw a pass that was intercepted by Marty Banks.
The Tasman pivot then bolted down the sideline, 95 metres in all, as he pushed Tasman's advantage out to 23-10 at the split.
The second spell got underway in frustrating fashion for the Magpies as West missed two penalty attempts in the opening seven minutes.
They enjoyed a weight of possession during the first 15 minutes of the second half but couldn't equate it in to any points as Tasman skipper Shane Christie was immense.
Eventually, Hawkes Bay's possession told and when Brendon O'Connor crossed with around 20 minutes left, the Magpies were right in the game as they were only behind 23-17.
A long-range penalty from Banks in the 70th minute proved vital when the newly-signed Hurricanes utility gave them a nine-point buffer.
West answered back shortly after, which sent the game to an exciting finish with only seven minutes left and when Eaton crossed it was all there for West but he couldn't make the connection.
Turning point: With a penalty only metres out from Tasman's line right on halftime, Hawkes Bay pivot Ihaia West tried to take a quick tap in search of a try but it backfired completely as Marty Banks snaffled an intercept and went 95 metres to score. Tasman then took a 23-10 lead to halftime and never looked back.
Warrior: Few blokes play 100 games for their home province these days but Hawkes Bay No 8 Karl Lowe marked that milestone tonight. The veteran loose forward is heading overseas at season's end and made his debut for Hawkes Bay in 2004.
Tasman 26 (Bryce Heem, Liam Squire, Marty Banks tries; Banks 3 pen, con) Hawkes Bay 25 (Zac Guildford, Brendon O'Connor, Chris Eaton tries; Ihaia West 2 pen, 2 con) Halftime: 23-10
- Daniel Richardson of APNZ