Cika wannan jumla:
2014, Mantha ya wakilci ƙungiyar Kanada a IIHF World Junior Ice Hockey Championships. Mantha shi ne babban mai zira kwallaye a Kanada, inda ya zira kwallaye biyar da mataimakansa shida a wasanni bakwai, kuma an kira shi zuwa 2014 WJC All-Star Team.