Club Atletico River Plate of Argentina have booked a place in the final of the Club World Cup, taking place in Japan.
The South American giants edged Sanfrecce Hiroshima by a lone goal, scored in the 72nd minute by Alario via a header, right in front of the goal post.
Hiroshima had beaten the African Champions, TP Mazembe on Sunday 3-0 at the quarter-finals.
River Plate will now await the result of the semi-final match between Barcelona FC and Guangzhou Evergrande of China being coached by Brazil’s Phil Scolaris.