Despite missing an open goal from two yards out against Juventus, the 30-year-old has backed his team-mate to ultimately prove his mettle once more in the Spanish capital
The France international has struggled this season, with his woes in front of goal compounded by the two-yard miss in the 2-1 victory over Juventus in the Champions League on Wednesday.
The 25-year-old has come in for criticism from his own fans, but Arbeloa believes the goal-shy striker will prove them wrong.
"Karim is important to us and that is why he has to keep working as he is," the 30-year-old told reporters.
"Benzema’s chance? It was a very difficult chance. He went in very strong and nearly scored. He is a great player that helps us a lot. Benzema will show people what he's worth and the fans will cheer for him."
Saturday will see the first Clasico of the current campaign take place in Catalunya, with Barcelona knowing victory would establish a six-point margin between Madrid and themselves.
The clash is scheduled to kick off at 18:00 CET.