Whakakihia te rerenga e whai ake nei: I te tau 2017, ko Mastromatteo tetahi waahanga o te kapa mētara koura i toa i te 4x100 whakakotahi i te
Ko te 2017 World Junior Swimming Championships. I te tau 2019, i wini a Mastromatteo i nga mētara e 3 i te 2019 World Junior Swimming Championships i Budapest, tae atu ki te mētara hiriwa takitahi i te 50 m breaststroke.