Newcastle United midfielder Tonali tapped home his first international goal 10 minutes into a hard-fought win at the King Baudouin Stadium.
Amorim's delay to join leaves Van Nistelrooy in charge at least for this weekend's visit by Chelsea, the Europa League home match to PAOK, and another clash with Leicester.
India defeated Germany 5-3 in the second game but lost the Bilateral Series in the shootout.
Rebecca Cheptegei made her Olympic debut in the women's marathon at the Paris Games, where she finished 44th.
Juventus underwhelmed in a goalless draw at Tuscany, creating very little against Empoli, while Bologna fought back from a two-goal deficit to pick up a point at Como.