McCrea said the midfield trio of Hemi, first-five Mitchell Millar and second-five Blair Osborne were able to breach the defence all game, once the pack got them some go forward.
Foster and Boult also made some great runs.
The win completed a good HYRC Series for Wanganui, who only lost to the Wellington Samoans and had back-to-back road wins over Poverty Bay and Wairarapa Bush, after the home victory over Horowhenua-Kapiti as well as beating Thames Valley in preseason.
"That was the goal right through - to try and beat these Heartland teams," said McCrea.
"Really good end to the season. The boys are stoked."