Slight, unassuming and incredibly timid, that all changes when he steps onto the football field.
Sure, he can’t change his build, but his stature rises when he calmly brings down a lob, turns his defender and races towards the opposition goal.
Tupani first hit the international scene in 2014 as a member of the Papua New Guinea U-20 side at just 15 years old.
For a player of that age to catch the eye of Oceania Player of the Century Wynton Rufer, you know there has to be some kind of special talent within.
And the youngster from Madang is proving himself worthy of Rufer’s confidence, and grateful for it.
“I really enjoyed the U-20s and having Wynton Rufer as a coach,” he says.
“It was a good experience to be learning with the older boys.”
Tupani wowed the crowd on the opening day of the OFC U-17 Championship in Apia, Samoa with his sheer speed, chasing down through balls and whipping around his marker like they’re not even there.
The young speedster savoured the experience of being among his peers, but it his late goal that will remain etched in the memory.
“I thought I played well,” he reflects.
“I scored one goal and was pretty happy. I could have scored a few more but I was pretty nervous.”
With the next encounter against Fiji on the horizon, Tupani says the butterflies are gone and he’s ready for the next one.
“I can’t wait until we play Fiji, until we win our next game.
“I watched them play New Zealand and I think that we will beat them…they are nothing.”
Big words from someone who usually has so little to say but as a senior member of the squad Tupani’s confidence is a boost to his teammates, many of whom had to apply for passports to attend this competition.
With every match taking them closer to the semi-finals, Papua New Guinea need all the self-belief they can muster and Tupani has them well on their way.
Papua New Guinea take on Fiji at 2pm on Thursday 15 January at J.S. Blatter Football Complex in Apia, Samoa.