Otago came from behind to thrash Southland and Tasman beat Waikato to get their respective Mitre 10 Cup campaigns under way with wins on Sunday.
Tasman, who were without New Zealand internationals Liam Squire and Kane Hames, left it late as an Alex Ainley try with six minutes to go edged them to a 24-19 home victory.
Both teams found it hard to put attacking moves together in blustery conditions, with wing Jordan Trainor finishing off a break by Willis Halaholo to give Waikato a first-half lead.
Tasman, semi-finalists in 2015, hit back through halfback Finlay Christie and Mitch Hunt kicked four penalties before Ainley crossed in the closing stages to secure a narrow victory.
The scoreline was much more comfortable for Otago, who won 40-17 at Southland, but they had to bounce back from falling to a 12-0 deficit.
Openside flanker Dillon Hunt scored just before half-time to get Otago on the board following four Wharenui Hawera penalties for the hosts and Otago did not look back after the interval, Teihorangi Walden scoring out wide to build momentum.
Wing Jaye Thompson-Te Muunu extended Southland's advantage to 17-10, but Michael Collins finished off a fine try before Walden recorded his second of the match.
Solid kicking from Fletcher Smith put Otago in a commanding position, before Josh Walden crossed late on to add gloss to the scoreline.