He scored two tries off the bench against the country of his father's birth and didn't look back,earning a start against Japan and New Zealand,which ended in a historic 24-0 win and Australia's first Oceania U20s title.
"He's awesome under the high ball,he's really good off the ground,he's very powerful,"Gilmore said.
"He's got a really good set of hands,he reads the game really well and he's got a big powerful body that he can use to beat defenders one-on-one and make good tackles in that wide channel."
On Tuesday Nawaqanitawase will be one of 28 players,from a variety of backgrounds and pathways,flying to Argentina to represent Australia in the U20s World Championships. Not bad for a kid who considered himself a"leaguie"until mid-way through high school and was playing second grade for Eastwood this season.
"At the end of the day we've got to pick our best 28 players to go across,it's a World Cup so you need the best in the country to do well,"Gilmore said.
"Not that it's bias,but not having preconceptions about players,which schools they've come out of,and if they've played representative footy or not,is important.
"[Centre] Kye Oates is another one,he went to Toowoomba Grammar and didn't play any state or national representative rugby at school.
"We've got our eyes open,it's performance and attitude that will get you through."
Australia open their campaign against Italy on June 4,before facing off against U20 Six Nations champions Ireland on June 13 and 2018 World Championship runners-up England on June 13.
It is a formidable line-up,with each nation under pressure to top their pool in order to advance. But insiders say this is Australia's most impressive U20s side in years,and they will head to Argentina with confidence and belief after toppling the Junior All Blacks only a few weeks earlier.
Nawaqanitawase will have his grandparents there with him,including an Italian grandfather he's had to wean off a life long passion for football.
"I still can't get my head around it. It's massive,"he said.
"I'd like to say I'm really lucky,but it's been a lot of hard work,really,to come from'nowhere'.
"My mum is so happy for me,for all the things I've had to do to get here,she's happy that I'm here and happy to be doing what I'm doing."