The seven-tries-to-two result looks decisive enough but the Barbarians were made to work hard to subdue the rugged Fijians.
"It was a very physical game so we had to make sure to get up in their faces," Trask said.
"We made sure to get the basics right and scored quite a few tries off the set piece.
"The ball was also quickly spread to our backs which tired them out."
New Zealand Schools also retained the Trans-Tasman Shield they have held since 2013 with a 32-22 victory over their Australian counterparts, after the Barbarians' Fijian contest.
Trask, who has now turned his attention to Sevens for the summer with Rotorua Boys' High, said he would be taking a more "professional" approach to his rugby - a valuable lesson he picked up from his Barbarian experience.
"I learnt so much over a short period of time," he said. "I'm looking forward to summer and will bring this experience with me."
"I'm delighted to have had the opportunity and all the lessons I have taken on board will only help my rugby development.
"The most important lesson I have taken away is professionalism. It felt as if we were playing professional rugby in a way.
"They got the best out of us because they expected a very high level and set us a challenge. I'll take this momentum with me."
New Zealand Schools and Barbarian Schools fixtures:
Monday, October 3
Venue: Mt Albert Grammar School
NZ Barbarians Schools 28 Australia Schools 17
NZ Schools 45 Fiji Schools 19
Saturday, October 8
Venue: Mt Albert Grammar School
NZ Barbarians Schools 46 v Fiji Schools 20
NZ Schools 32 v Australia Schools 22