Neymar opened the scoring in the 51st minute and provided the last pass for Firmino's clincher in the 88th. Firmino tapped in from close range minutes after coming on as a replacement for Coutinho.
For the opener, Neymar slid toward the goal and tapped in Willian's low cross from the left.
The goals made Brazil the World Cup all-time scoring leader with 228 goals, surpassing Germany with 226.