The Mount Maunganui effort lifted markedly after the break but their passing and handling skills - as well as an awareness of the open space on the flanks and behind a fast-charging, flat Aquinas backline - failed to follow.
A flurry of ruck, offside and time-wasting penalties resulted in Collins and Wilson each spending time in the bin, but the lateral Mount attack struggled to make the two-man advantage count.
Daniel Pushart managed a converted try to narrow the margin to 15-7 with about 10 minutes to play, but they struggled to make more inroads once Aquinas returned to the full 15 players.
Co-coach Shane Wilson said his players - whose heads were shaved in a $2000 fundraising effort following a Te Wharekura o Mauao player's diagnosis with bone cancer - said the side still had plenty of work to do.
"We've actually only had six training runs and one training match, against Bethlehem College, so there are some pleasing things, but there is a lot we can work on," Wilson said.
"A few of our big boys need to lift their fitness levels after Saturday.
"Unfortunately, we don't have depth - we've only got 22 senior rugby players," he said.
"They are all in and you have to use what you've got, but they settle into the team really quickly."
Aquinas College 20 (Aronia Solomon, Te Nawe Ngatai, Dion Collins, Reed Wilson tries) beat Mount Maunganui College 7 (Daniel Pushart try; Pushart con).