Real Madrid are trying to win their 12th Spanish Super Cup.
Real Madrid beat Barcelona in extra-time to reach the Spanish Super Cup final.
Ansu Fati's late equaliser forced extra time in Saudi Arabia, and Federico Valverde scored the winner.
Real took the lead three times in the El Clasico clash, with the other two teams coming back twice.
Benzema scored and assisted in normal time, but Luuk and Fati scored in the second half.
The Spanish Super Cup semi-final is over.
Benzema, who played in Vinicius Junior for the 25th-minute opener, also hit the post in normal time and came close to extending Real's lead with minutes to go in extra time.
Vinicius' pace on the counter-attack caused problems for Barcelona.
Ousmane Dembele and substitute Pedri and Fati were able to create opportunities, but they were not able to convert them.
There was a full Barcelona debut for a former Manchester City player, but he did not get on the score sheet before being taken off at the half-time break.
The winner of Thursday's Athletic Bilbao-Atleti Madrid match will face Real Madrid in the final of the Super Cup in Riyadh on Sunday.