City made the most of Takahiwai's sloppy play as they brought the margin to within eight points in the first half to have the score sitting at 20-12.
However, Hool's stern words seemed to do the trick as Takahiwai came out firing.
"Half-time came round and I gave them a bit of a rark up," Hool said. "Then they went back out and stuck to the game plan, so it was good.
"We probably should have won by more but went off the game plan and got a bit scrappy with ball skills."
Hool recognised player of the day Jessie Epiha's contribution to the game as he made his return after a season away from the game. Another strong contributor for Takahiwai was captain Ed Wilson, who took the ball forward all day to give his side strong front foot ball.
Hool credited the condition of Fishbone Park in Otangarei as being in good nick considering the lack of rain Northland has seen recently.
In other premier rugby league matches over the weekend, the Portland Panthers were victorious over the Hora Hora Broncos by 34-28; the Hikurangi Stags were too strong for the Northern Wairoa Bulls 50-12; Muriwhenua Falcons breezed past the Kerikeri Slayers 54-10; while the Moerewa Tigers beat the Hokianga Pioneers 36-22.