Mid Northern missed the leadership of Jason Hammond in the pack, but were also missing Dylan Horne, Will Whetton and Mark McCluggage and will be anticipating a rematch later in the season.
In Whangarei, Old Boys came good in the second half to score four tries and dismiss Otamatea's challenge.
Old Boys started well and took an early lead before the Hawks surged back into contention, dominating the second quarter to trail by just two points at the break.
Coach Boyd Matson had a few choice words of advice for the team at half-time and it seemed to pay off with the forwards once again taking control.
"They were going wide too early so I told them to be more direct up front and once they did that, they began to make progress and we began to score the points," Matson said.
Old Boys' backs Troy Gilbert and Dan Wells scored doubles.
Hora Hora soaked up a ton of pressure from Marist in the final quarter to pip their hosts 21-19 at Kensington Park. The win keeps alive their faint playoff hopes, while denting Marist's, with the home side dropping into fifth place behind Kamo. Kamo snapped their two-match losing streak with a 22-19 win away from home at Hikurangi. Kamo were trailing 19-8 going into the final quarter but a try to Cam Goodhue and then another right on the hooter to Matt Wallace gave them a boost with five games to go before the playoffs.
Mid Western remain in second place with a bonus point 33-10 win over the Western Sharks.