Skipper David Morgan and prop Malcolm Mills were sent to the bin for fighting.
The last time Otamatea beat Wellsford was 17 years ago.
Otamatea winger Michael Tovine scored a brace while halfback Nalu Tuigamala and blindside flanker Trevis Larsen bagged one each.
Mant said with hooker Matt Moulds and prop Lance Vale joining the team this week, he expected an improvement in their scrum and lineout during their clash with Hora Hora.
Despite the sobering loss, Mant said their performance had improved considerably from the initial rounds when the team was thrashed by more than 50 points by Mid Northern and Wellsford.
In other action, Hora Hora thrashed premier newcomers Waipu 52-32.
Winning coach Mark Wati said it was a tough game as Waipu pushed his players for the full 80 minutes and scored a few tries from Hora Hora's mistakes.
Hora Hora led 26-22 at half time and Wati said his players managed to get some dominance in the second spell and piled another 26 points. His team also won the first round 39-10. Wati said Waipu was a lot stronger than Kamo who Hora Hora beat 60-6 on June 8.