Luka Dončić (age 19.9 years) guarded by Kawhi Leonard of the Toronto Raptors. With 35p-10a-12r, Luka had the first 30p triple double as a teenager in the NBA. Unfortunately it was not enough, the Mavs lost 123:120 with the help of superstar Kawhi Leonard who went 33p-2a-11r (read the recap).
Source: TSN Sports