Real Madrid extended their unbeaten run to 36 games by beating Club America 2-0 to reach the Fifa Club World Cup final against Kashima Antlers on Sunday.
Karim Benzema gave the European champions the lead with a clipped finish after a Toni Kroos pass.
Cristiano Ronaldo sealed the win by drilling in a strike in added time but there was confusion around the goal.
Referee Enrique Caceres briefly asked for a video assistant consultation before allowing the goal to stand.
This year’s Club World Cup is the first tournament to use video assistant referees. A pitchside monitor is available to referees to review decisions.
However, Caceres did not view the incident on the monitor before restarting the game and awarding the goal.
In the other semi-final, referee Viktor Kassai stopped the game after being alerted to an incident by his assistant, then viewed footage on a monitor and gave a penalty to Kashima Antlers in their win over Atletico Nacional.
The Club World Cup features champion club sides from each of Fifa’s six continental confederations.
Before Real Madrid’s match began, there was a minute’s silence at the Yokohama Stadium, in tribute to the victims of the air crash on 28 November that killed 71 people, including 19 players and staff of Brazilian team Chapecoense.
Ronaldo, who won the Ballon d’Or for a fourth time earlier in the week, had hit the post with a glancing header from Lucas Vazquez’s cross before Benzema scored.
The Portuguese then had a shot blocked and headed wide before scoring.