The hosts scored eight tries through Troy Cullen, Denver Patua, Mitchell Reader, Wiki, Roberts-Tenana, Micky Seymour and a pair for Blomfield.
The match went back and forth as Flynn Rolton, Jake Brown and Taremon scored second-half tries, leading Mid Northern to a 43-36 lead late in the contest.
OBM brought it within two points before a last-minute penalty gave them an opportunity to snatch victory.
Blomfield duly crossed underneath the black dot to wrap up a clinic of attacking rugby from both sides.
Meanwhile Kamo sent a message to the rest of the competition with a commanding 36-15 victory over Hikurangi.
Led strongly by flanker Josh Goodhue and halfback Mac Sykes, Kamo proved far too good for Hikurangi.
The Northland midfield pairing of Blake Hohaia and Tamati Tua combined well on both ends of the field.
Kerikeri announced themselves to the top flight competition with a 45-7 victory over Otamatea.
Kerikeri gained promotion after toppling Mid Western 18-0 in the promotion/relegation fixture last year and showed they want to be a force in the Premiership.
Otamatea were close to the relegation zone last year and will be hoping for a quick turnaround.
Hora Hora meanwhile easily beat Waipu 43-17 in the battle of last year's beaten semi-finalists.
Waipu worked hard but Hora Hora were too classy through the middle stages of the contest.
The final match of the round saw Wellsford defeat Western Sharks 32-24.
Kamo, OBM and Kerikeri completed opening round doubles for their clubs as they all picked up wins in the Premier Reserve competition.
Kamo kicked off their title defence with a resounding 55-12 home win over Hikurangi as inside backs Diani Timms and Adam Sheppard led them expertly around the park.
OBM also looked strong as they attempt to go one better in 2018 after losing the final last season. Taking on Mid Northern at home, they came out 38-20 winners.
Kerikeri also got off to a great start, racking up a half-century of points as they routed Otamatea 58-17.
It was a round for big victories in the reserve grade as Waipu's 46-12 victory over Hora Hora and Wellsford's 38-21 win over Western Sharks also ending with fairly wide margins.
Bayleys Northland Club Rugby results Premier:
Kamo 36-15 Hikurangi
Old Boys Marist 48-45 Mid Northern
Otamatea 7-45 Kerikeri
Waipu 17-43 Hora Hora
Western Sharks 24-32 Wellsford
Premier Reserve:
Kamo 55-12 Hikurangi
Old Boys Marist 38-20 Mid Northern
Otamatea 17-58 Kerikeri
Waipu 46-12 Hora Hora
Western Sharks 21-38 Wellsford