Los Blancos beat Barcelona to the title after lockdown thanks to a run of 10 straight victories, before a 2-2 draw at Leganes on the final day of the season.
Zinedine Zidane's side are now preparing for their last-16 second leg against City in Manchester on August 7, when they will look to overturn a 2-1 deficit to advance to the final phase in Lisbon.
"LaLiga was really special and also difficult, but we did a great job," Benzema said after collecting an award for LaLiga's best player from Mahou on Thursday.
And looking ahead to the club's European date next week, he added: "The team is good. Now we have time to work.
"We want to continue as we were in LaLiga and win against City, which is very important."