The Portuguese forward looked in ominous form on Saturday on his return from a two-match La Liga suspension, netting twice as Real crushed bottom club Xerez 3-0, but Puel told Spain's Marca sports daily they would not be marking him man-to-man in the last-16 first-leg clash at the Stade de Gerland.
"We cannot just focus on Ronaldo as there are other players who can make the difference," he said in an interview published on Sunday.
FEATURE:Real Madrid prepare for their annual knock-out round
"There is so much potential that I don't believe that one player will make the difference," he said, listing Brazilian playmaker Kaka, former Lyon striker Karim Benzema and Argentina forward Gonzalo Higuain as significant potential threats.
Lyon defeated Real on the last two occasions the clubs met in France, although Manuel Pellegrini's side are unbeaten away in this season's Champions League and invested around 250 million euros in players in the close season.
They are seeking a first quarter-final place since 2003/04 and this year's competition has a special edge for the nine-times European champions as May's final is at their Bernabeu stadium.
Benzema had been a doubt after picking up a muscle problem, but Real said on their website on Sunday the 22-year-old France international had been included in the squad to face the club he played at from 2005-2009.
"It was important for him to leave Lyon and continue his development," Puel told Marca.
"He has arrived at one of the great clubs with a lot of individual talents and he has to fight for a place in the team," he added.
GREAT GOAL
Lyon have struggled this season, going out of both the French Cup and the League Cup, and ended 2009 in sixth place in Ligue 1, 13 points adrift of Girondins Bordeaux who pipped them to the title last season.
They are back up to fourth after Saturday's 1-0 home win over Racing Lens.
"We are not playing brilliant football but we have improved," Puel said.
"We need to be more competitive, above all against Madrid," he added.
"It's a very important match because we have always got to the last 16 and we are one of the most consistent teams in Europe but we need to grow and get further in the competition, it's our great goal."
