Pedzisa mutsara unotevera: Barnes akahwina menduru yegoridhe neUnited States ku2017 FIBA Under-16 Americas Championship muFormosa, Argentina mushure mekunge avhareji ye9.8 mapoinzi, 3.2 rebounds uye 2.4 inobira pamutambo. Mukukunda semifinal pamusoro peArgentina, akatungamira vese vanorova zvibodzwa nemapoinzi makumi maviri nematanhatu ekuba uku achityora rekodhi reAmerica pasi pegumi nematanhatu muzana yekukanda mahara nekupfura 8 kubva pa8 kubva pamutsetse wekukanda mahara. Pa2018 FIBA Under-17 World Cup muArgentina, Barnes akaenzana 9.5 mapoinzi uye 5.8 rebounds pamutambo uye akabata imwe menduru yegoridhe. Akaenzana 9.7 points, 4.9 rebounds uye 2.7 assists pamutambo pa
2019 FIBA Under-19 World Cup muHeraklion, Greece, kwaakakunda menduru yake yechitatu yegoridhe neUnited States.