Al Nasr lost 3-1 to the European powerhouse at the 2000 Club World Cup and allowed a number of players from other Saudi clubs to line-up against the visitors.
Real took the lead through Arjen Robben five minutes after the break.
Saudi Arabia striker Malek Maaz equalised after 54 minutes and then the hosts went to town.
Iraqi star Nashat Akram gave the Saudis the lead just a minute later and on the hour Saud Khariri extended the lead.
There was still time for Maaz to grab his second and his team’s fourth to send the fans home happy.